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98.0.2 stopped outgoing email with attachments (Windows 10 64 bit)

  • 2 replies
  • 1 has this problem
  • 6 views
  • Last reply by Toad-Hall

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Since the last update, my ATT outgoing emails that have attachments (all sizes, none more than 20 MB) are not going through.

See attached error message.

I can send these directly by saving as a draft and using my ATT/Yahoo mail however, so I doubt that ATT is the block.

Since the last update, my ATT outgoing emails that have attachments (all sizes, none more than 20 MB) are not going through. See attached error message. I can send these directly by saving as a draft and using my ATT/Yahoo mail however, so I doubt that ATT is the block.
Attached screenshots

All Replies (2)

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Yahoo says: The sum of all attached files in a single message, both for incoming and outgoing email, must not exceed 25MB in total file size.

So it must be lower than 25MB.

Please note: An email will be a lot larger than the size of the attachment because 25MB is computed after Base64 encoding. Therefore size of email will increase by about 30%.

You will have the email content itself plus attachment. If you add the attachments and save as draft, you will be able to see the email size before encoding. The absolute max would be under 19MB as after encoding the real size of email will be about 25MB which is on the limits. That is also assuming the email itself is simple text and nothing copy pasted from eg: MSWord which will bloat the email considerably. I would keep to about 17MB max.

Also, just because the server may be able to send email up to 25MB, there is also the receiving server to consider. Whilst many servers have 25MB limit, it is not all servers, some may have their limits lower, so email might get sent but can not be delivered.

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It is also worth checking to see if your Anti-Virus is causing the problem as it is possible it is scanning file.

The only true way to test if Anti-Virus is the cause: Exit all programs and then reboot the computer in 'Safe Mode with Computing'. then start Thunderbird and try sending. Please note: you may find wireless connections will not allow 'Safe Mode with Networking' - you will need to use ethernet cable to connect to router/hub.