[JENKINS-68518] Email-ext treats transient SMTP errors as fatal errors

[jenkins-infra-bot]

I have an email server that occasionally returns an SMTP 421 error when Jenkins tries to send an email.  According to the SMTP specification, this is a transient error, however email-ext treats it as a permanent error and gives up on sending the message.

It would be better if email-ext could recognize SMTP 4yz errors as transient, and wait and try again instead of failing immediately.

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Originally reported by anfrind, imported from: Email-ext treats transient SMTP errors as fatal errors

• assignee: slide_o_mix
• status: Open
• priority: Minor
• component(s): email-ext-plugin
• label(s): email-ext, smtp
• resolution: Unresolved
• votes: 0
• watchers: 1
• imported: 20251211-193728

Raw content of original issue

I have an email server that occasionally returns an SMTP 421 error when Jenkins tries to send an email.  According to the SMTP specification, this is a transient error, however email-ext treats it as a permanent error and gives up on sending the message.

It would be better if email-ext could recognize SMTP 4yz errors as transient, and wait and try again instead of failing immediately.