Jellyfish Error Codes

In some cases, outgoing emails for Spacemail, Namecheap Private Email, and Shared Hosting services are bounced back with the "Rejected due to a high probability of spam" reason. In this case, the bounce-back email will contain the reason why the email was rejected prompting users to fix the issue and try again.

Here’s the list of possible error codes:

Error code	Explanation
JFE040000	Rejected due to high probability of spam. Please reach out to us if you need to get more details: - For Private Email and Shared Hosting users: please contact us via Live Chat at https://www.namecheap.com/help-center/live-chat/ - For Spacemail users: please reach us out via Live Chat at https://www.spaceship.com/about/contact-us/
JFE040001	Our system classified the content of your email as being similar to known spam patterns. Please consider changing the wording of your message to avoid phrases and sentences common for unsolicited emails. You may find suggestions on improving your content in our guide: Why emails go to spam and what to do
JFE040002	The message contains a file with an untrustworthy extension. Please refrain from adding attachments with this extension, or use an alternative method to share the file.
JFE040003	The domain in your message has a poor reputation and is on a blocklist. Please contact the relevant blocklist provider to request delisting.
JFE040004	Your email content corresponds with (or is similar to) a known spam pattern that is filtered by our system. You may find suggestions on improving your content in our guide: Why emails go to spam and what to do
JFE040005	The domain in your message has a poor reputation and is on a blocklist. Please contact the relevant blocklist provider to request delisting.
JFE040006	The URI in your message has a poor reputation. Please remove it and try again.
JFE040007	Your message contains a URL with phishing-related content. To resolve this, remove or replace the URL in question. If the domain in the URL is in your administration, we recommend removing it from blocklists first.
JFE040008	The subject line in your email contains only uppercase letters. Consider removing excessive capital letters from the subject line as it can be considered as spam-like behavior.
JFE040009	Your "multipart/alternative" message contains an odd number of URIs. Check that both the plain text and HTML versions of your message have the same number of URIs.
JFE040010	The "Message-ID" header is incorrectly formatted or missing. To resolve this, ensure that the email server generates unique and properly formatted "Message-ID" headers for each email, following the RFC 5322 guidelines.
JFE040011	The sender seems to be forged, as the email address in the "From" field does not correspond to the mailbox from which the email is sent ("envelope-from" field). Please make sure that the sender is the same in both the "From" and "envelope-from" fields.
JFE040012	The message body contains a text part encoded in Base64 format that does not contain any 8-bit characters (which means it might contain binary data or a malicious script). Remove Base64 encoding to allow your message to be sent.
JFE040013	The message’s "MIME-Version" header is incorrectly formatted. MIME headers are case-sensitive. You used "Mime-Version", but the correct version according to RFC 822 is "MIME-Version". Please correct the header formatting before resending the email. This can be adjusted in your script, mail client software, or mailing application settings.
JFE040014	The HTML and text parts of your message do not match. Please ensure the content is the same in both, then try sending the message again.
JFE040015	The subject of the message contains a "Re:" prefix, but it does not appear to be a reply. Please avoid using the "Re:" prefix unless you are responding to a message. To reply properly, use the Reply button in your Webmail or email client.
JFE040016	The subject line in your message contains non-7-bit characters and must be encoded according to RFC rules (RFC 2047 and RFC 6532) to ensure correct rendering across email platforms. To fix this, ensure the special characters in the subject line are encoded. If you’re using any mailing software, check it for misconfigurations.
JFE040017	The message is missing its "Message-ID" header. To resolve this, make sure your email server or client generates and includes a unique "Message-ID" for each outgoing message.
JFE040018	Subject line contains currency symbols which may be indicative of spam or phishing. Please remove the currency signs or terms commonly associated with financial solicitations from the subject line.
JFE040019	The message has a date header specifying a timestamp in the past. To fix this, ensure that the system time on your email server is correctly configured and synchronized with a reliable time source before resending the email.
JFE040020	The message has a date header specifying a timestamp in the future. To fix this, ensure that the system time on your email server is correctly configured and synchronized with a reliable time source before resending the email.
JFE040021	The message contains an IPFS (Interplanetary File System) gateway URL, which is often associated with malicious emails. Please refrain from using IPFS URLs in messages, and consider using alternative non-IPFS links.
JFE040022	The subject line in the message is heavily encoded in Base64 format, even though it lacks non-Unicode characters. This may result in the recipient's mail client decoding the subject incorrectly. To fix the issue, avoid encoding subjects, specifically as mail clients should do it for you where needed.
JFE040023	The subject line ends with a question mark which can be a characteristic of spam or phishing attempts. Please remove the question mark in the subject line.
JFE040024	The message is missing the "MIME-Version" header. To fix this, ensure your email includes a "MIME-Version" header with the appropriate version number. This can usually be set in your mailing script or email application.
JFE040025	The introduction at the beginning of the email has triggered our anti-spam filter. Please reformat the introduction part in the beginning of the email.
JFE040026	The recipients in the message’s "envelope-to" and "To" headers do not match, which could indicate a possible spoofing attempt. Please make sure you provide the same recipients in both the "envelope-to" and "To" fields.
JFE040027	The "From" header in your message contains encoded characters, but all symbols are 7-bit, so Base64 encoding is unnecessary. Please check your scripts or mailing applications — there may be a non-printable or malicious character that needs to be removed.
JFE040028	The message content primarily consists of URLs, which can be a characteristic of spam or phishing emails. To address this, consider adding more meaningful content to your email, and avoid messages that only contain links.
JFE040029	The message contains the email address that has a poor reputation. Please contact the relevant blocklist provider to request delisting.
JFE040030	Content-Transfer-Encoding (CTE) for some parts of the email is set to 7-bit, which may not be appropriate for certain content types. To fix this, ensure that the CTE is correctly configured based on the content, using alternatives like quoted-printable or Base64 for non-ASCII characters. Also, you can check the mailing script or the mailing software you are using to adjust the Content-Transfer-Encoding appropriately.
JFE040031	The message is missing a plain text part, which is considered untrustworthy and can also affect accessibility. Please either add a plain text version of the email or check that your email client is configured properly to generate this when a message is created.
JFE040032	The "Reply-To" header in the message contains a domain that differs from the one used in the "From" header. This can be seen as untrustworthy, since spammers often use this technique to spoof replies. Please correct this and resend your message.
JFE040033	The recipients in the message seem to be auto-generated. Please avoid sending emails to more than 5 recipients at once if the addresses are similar or seem like automatically generated addresses.
JFE040034	X-Mailer header indicates a very old Mail User Agent version. Update your mailing software to the latest version to resolve this issue.
JFE040035	Your message contains a suspicious URL. To resolve this, remove or replace the URL in question.
JFE040036	The display name in the "From" header is the same as the sending email address. Please avoid using email addresses as display names, as this is often associated with spam-like behavior.
JFE040037	The message is missing the "Date" header, which is essential in indicating when the message was sent. Without it, the message is not compliant with RFC 5322 formatting standards. Please add a "Date" header in the correct format (e.g., Date: Wed, 20 Mar 2025 12:34:56 +0000) and try sending your email again.
JFE040038	The "Reply-To" header in the message is the same as the "To" address, but it should lead to the same domain as the "From" address. Please adjust the "Reply-To" address and resend your message.
JFE040039	The message is missing the "To" header. This can occur if the mailing script or agent is misconfigured, or due to a mail server issue. Please ensure the "To" header is present and try resending the email.
JFE040040	Rejected due to high probability of spam. Please reach out to us if you need to get more details: - For Private Email and Shared Hosting users: please contact us via Live Chat at https://www.namecheap.com/help-center/live-chat/ - For Spacemail users: please reach us out via Live Chat at https://www.spaceship.com/about/contact-us/
JFE040041	The local-part (the portion before the "@" symbol) of the recipient's email address — including those in the "To", "CC", or "BCC" fields — must follow the formatting rules defined in RFC 5321. This includes restrictions on characters, length, and placement of special symbols. For example, user name@example.com are invalid, while username@example.com is valid. Please correct the local-part format according to RFC 5321 before resending your message.
JFE040042	According to RFC 5322, a space must separate the header name from its value. If it’s missing, the message will be rejected. For example, Subject:Hello is incorrect, while Subject: Hello is correct. Please review your headers and ensure there is a space after the colon before resending the message.
JFE040043	The "From" header specifies the sender and is required by RFC 5322. If it's missing, the email is considered incomplete and will be rejected. Make sure your email-sending application or script includes the "From" header (e.g.,From: sender@example.com), then resend your message.
JFE040044	Only one "From" header is allowed in an email, according to RFC 5322. Multiple "From" headers are invalid and will be rejected. Please review the headers, keep only one "From" header, and resend the message.
JFE040045	The "From" header contains an incorrectly formatted or invalid email address. According to RFC 5322, the format should be Sender, where “Sender” is the display name,user is the local-part, and example.com is the domain. Please correct this and try resending the message.
JFE040046	The domain used in the "From" header must be a fully qualified domain name (FQDN) according to RFC 5321. This means it should include both the domain name and the top-level domain (e.g., example.com). Please correct this and resend your message.
JFE040047	The domain used in MAIL FROM in an email's envelope needs to be a fully qualified domain name (FQDN) according to RFC 5321. This means it should include both the domain name and the top-level domain (e.g., example.com). Please correct this and try resending the email.
JFE040048	The "MAIL FROM" address in the email envelope is incorrectly formatted or invalid. According to RFC 5321 specifications, the "MAIL FROM" address must be a properly formatted address like , where user is the local-part and

You may receive a bounce-back message with one of the following error codes when sending emails to Spacemail, Namecheap Private Email, or Shared Hosting addresses.

JFE030050: This error usually indicates a delivery issue related to the recipient’s mailbox or domain. Make sure the mailbox exists and is not full, and that the domain is registered and active. If the domain was recently updated, DNS propagation may still be in progress — wait up to 72 hours and try again.
JFE030070, JFE030071, JFE030072 - may occur both when sending and receiving emails

If the problem continues with any of these errors, please contact our Support Team via Live Chat:
- For Namecheap Private Email and Shared Hosting users – chat with us here
- For Spacemail users – chat with us here

Associated articles

Why emails go to spam and what to do

What is Jellyfish?

How to log into Jellyfish dashboard

Updated

4/18/2025

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