What causes 4003 and 4004 Gmail soft bounce errors and how to resolve them?

Email marketer from StackOverflow user EmailFixer responds that such errors frequently stem from temporary network hiccups or DNS resolution failures on the recipient server's side. A simple retry mechanism in your sending process can automatically handle these.

Email marketer from SendPulse notes that soft bounces occur due to transient issues, like server downtime or network problems. Retrying the send after a delay can often resolve the issue if the problem is temporary.

Email marketer from Reddit user u/EmailGuru shares that experiencing 4000 series errors, particularly with Gmail, often points to temporary server-side glitches. The advice is to wait and retry sending the email, as the issue usually resolves itself.

Email marketer from ActiveCampaign suggests monitoring bounce rates closely. While not specific to 4003/4004, high soft bounce rates generally warrant investigation into server health or potential network issues. Ensure your sending infrastructure is stable.

Email marketer from Email on Acid generally advises investigating high bounce rates, and to ensure your sending domain has proper DNS records (SPF, DKIM, DMARC) to avoid being flagged as spam. They suggest these configurations can sometimes impact how receiving servers handle incoming mail, triggering temporary bounces.

Email marketer from Quora user TechEmailExpert explains that those bounce errors often result from overloaded recipient servers or temporary routing problems. Implementing exponential backoff retry logic can help the sending server automatically retry sending the email during quieter server moments.

Email marketer from Mailjet shares that soft bounces often indicate temporary issues like a full inbox or server problems. While 4003/4004 isn't explicitly mentioned, general advice includes checking recipient validity and retrying sends.

Expert from Word to the Wise, Laura Atkins, explains that while specific 4003/4004 errors aren't universally defined, they generally indicate temporary delivery issues. These can range from overloaded receiving servers to network routing problems. Resolution often involves retrying the message after a delay.

Expert from Email Geeks explains that the 4003 and 4004 errors indicate an inability to reach receiving servers, likely a temporary networking problem unrelated to spam filtering, suggesting a resend of the message.

Documentation from RFC 3463 clarifies that 4.X.X SMTP codes signify transient failures. These failures mean the request couldn't be completed but may succeed if retried. Specific codes like 4.3.1 (Mail server failure) could relate to 4003 or 4004, suggesting temporary server issues or routing problems.

Documentation from Google Workspace Admin Help explains that a 400 series SMTP error generally indicates a temporary issue on the receiving server's end. 4003 may indicate a server overload or temporary unavailability, while 4004 points to DNS or network routing problems. Retrying the message delivery later is recommended as a resolution.

Documentation from Microsoft explains that While not specific to Gmail, Exchange Server uses similar codes. A 4.4.7 error (similar in concept) indicates a delivery delayed status due to network congestion or server unavailability. Resolution involves waiting and automatic retries by the server.