Why are authenticated emails from valid senders bouncing in Gmail with timeout errors?
Summary
What email marketers say16Marketer opinions
Email marketer from GlockApps details that Gmail uses rate limiting to prevent abuse. Exceeding sending limits can result in temporary errors and bounces, even if you are properly authenticated.
Email marketer from Email on Acid shares that spam filters analyze email content and structure. Even authenticated emails can be flagged if the content resembles spam.
Email marketer from Email Geeks confirms they have either quarantine or reject policies.
Email marketer from Reddit explains that using shared IP addresses can lead to deliverability problems if other users on the same IP are sending spam. Even with proper authentication, your emails can be affected.
Email marketer from Hubspot mentions that a low sender engagement rate (low opens, clicks, replies) can damage the IP and domain reputations. This can lead to deliverability issues, despite proper authentication.
Email marketer from Email Geeks wonders if it's related to the Verizon outage, speculating it might have been a DNS blip.
Email marketer from Email Marketing Forum shares that issues on the sending server (e.g., overload, network problems) can cause temporary failures, even if authentication is correct.
Email marketer from Email Geeks agrees that it was likely a DNS issue causing the high Gmail bounces, as the senders sent at the same time.
Email marketer from Neil Patel explains that poor email deliverability can sometimes be caused by sender reputation issues. Even with proper authentication, a low sender reputation can lead to bounces.
Email marketer from StackExchange explains that greylisting (temporarily rejecting emails from unknown senders) can cause temporary delivery failures. Gmail may temporarily reject emails initially, even if authenticated.
Email marketer from Email Geeks shares that they noticed elevated Gmail bounces over the weekend, even from properly authenticated senders, with a timeout error message related to rate limiting due to unauthenticated email.
Email marketer from Mailjet shares that DNS issues, such as incorrect DNS records or DNS server outages, can cause temporary failures in email delivery, even if authentication is set up correctly.
Email marketer from Litmus shares that being listed on a blocklist (blacklist) can cause delivery issues. Even with proper authentication, emails from a listed IP or domain will likely be blocked or bounced.
Email marketer from Email Geeks confirms that the emails have SPF and DKIM alignment.
Email marketer from SendGrid explains that IP address reputation plays a significant role in deliverability. If your IP address has been used for spam in the past, even authenticated emails may experience bounces or delivery delays.
Email marketer from Email Geeks votes for DNS as the cause and mentions seeing Gmail bounces for IPs that supposedly lacked PTR records, which points to a DNS outage.
What the experts say7Expert opinions
Expert from Spamresource explains that Gmail can sometimes be aggressively filter emails if it suspects something 'spammy'. Even if authenticated, a 'spammy' email will be deferred or delayed. This can cause timeouts if the deferrals reach Gmail's internal retry limits.
Expert from Spamresource explains that temporary DNS resolution issues at the sending server can cause timeouts. Gmail, seeing a timeout, may return a temporary failure. While authentication is in place, the underlying network infrastructure might be at fault.
Expert from Email Geeks asks if the mail is aligned.
Expert from Word to the Wise shares that if a sender suddenly increases email volume, even with authentication, it could trigger rate limiting by Gmail, leading to temporary failures and timeout errors. This is because Gmail views sudden high volumes from a sender with caution.
Expert from Email Geeks asks if senders are publishing a DMARC record.
Expert from Email Geeks suggests it could be DNS problems.
Expert from Email Geeks asks if the DNS provider is ultradns (or whoever they are now), mentioning they had significant problems over the weekend.
What the documentation says5Technical articles
Documentation from RFC 5321 details SMTP timeouts, explaining that the server should generally wait at least 5 minutes for the completion of each SMTP command. Timeouts can occur due to network congestion or server issues.
Documentation from DMARC.org explains that a strict DMARC policy (e.g., reject) combined with authentication failures can lead to emails being bounced. Ensure SPF and DKIM are aligned with your DMARC policy.
Documentation from Google Workspace Admin Help explains that a temporary error means the message can't be delivered right now. The sender doesn't need to take action, as the server retries delivery for up to 5 days. The message is returned to the sender if delivery still fails.
Documentation from Microsoft Learn explains that a misconfigured SPF record can cause authentication failures. Ensure the SPF record is correctly set up to authorize sending servers.
Documentation from DKIM.org explains that problems with the DKIM signature (e.g., incorrect key, signature mismatch) can lead to authentication failures and bounces, even if SPF is correctly configured.