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SMTP Username keeps swapping between two accounts causing sending errors

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  • 1 masɔmasɔ sia le esi
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  • Nuɖoɖo mlɔetɔ Toad-Hall

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I have two email accounts set up in Thunderbird and have been using them for years. Just started to get a sending error 550.5.1.0 sender xxxx@charter.net rejected on the main account. So I went in a looked at both accounts smtp settings and email account 1 had account 2's username under edit smtp. So I changed it to the correct one( account 1 username) and it would send, Then account two would get the error when sending. After checking, every time I change the username to the corresponding account user name, it changes the other accounts username as well. I have another computer with several different emails and they all have the correct username under smtp settings.

If anyone can advise as to the cause, if there is some corruption in Thunderbird, or have experienced a similar issue it would be appreciated. Iam computer savvy, but this one's got me perplexed.

Much thanks

I have two email accounts set up in Thunderbird and have been using them for years. Just started to get a sending error 550.5.1.0 sender xxxx@charter.net rejected on the main account. So I went in a looked at both accounts smtp settings and email account 1 had account 2's username under edit smtp. So I changed it to the correct one( account 1 username) and it would send, Then account two would get the error when sending. After checking, every time I change the username to the corresponding account user name, it changes the other accounts username as well. I have another computer with several different emails and they all have the correct username under smtp settings. If anyone can advise as to the cause, if there is some corruption in Thunderbird, or have experienced a similar issue it would be appreciated. Iam computer savvy, but this one's got me perplexed. Much thanks

All Replies (2)

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You should have a separate smtp for each account, even if the server is the same. Create the servers, if they don't already exist, in Tools/Account Settings, Outgoing Server (SMTP) at the bottom of the left pane. Enter a unique Description, e.g. smtpcharter1 and smtpcharter2, and match the User Names with the corresponding accounts. Then, select an account in the left pane of Account Settings and select the correct server in the Outgoing Server (SMTP) drop-down in the right pane.

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Sounds like you have managed to get both accounts using the same smtp server.

  • Right click on mail account name in Folder Pane and select 'Settings'
  • Bottom left click on 'Outgoing server (SMTP)'
  • Select first outgoing server in list
  • click on 'Edit'
  • Description: this field is so useful but rarely used to full benefit of user.
  • Type in the email address of account that uses that smtp server, it should match the username.
  • click on OK
  • Now select the second smtp in list.
  • click on 'Edit'
  • Description: Type in the email address of the second account that uses that smtp server, it should match the username, so make sure it is correct.
  • click on OK


Now make sure each of the mail accounts in the left pane is actual using the correct smtp server.

  • select the mail account name.
  • bottom right it will say what smtp it is using. This time you will see the 'Description' and it should show the same email address as the account, if it does not then click on dropdown and select correct one.

When checked all accounts are using correct smtp, then click on OK

Restart Thunderbird to ensure all settings have been fully updated.