Try disabling each of your add-ons in turn, then try sending an email. You may find one of your add-ons is not compatible with v 45.0.

pigeonsontheroof said

Try disabling each of your add-ons in turn, then try sending an email. You may find one of your add-ons is not compatible with v 45.0.

Only had Lighting and theme font as add-ons turned off, still have same problem.

Please try this: MAC 'Thunderbird' > 'Preferences' > 'Advanced' > 'General' tab click on 'Config Editor' button in top search type: auth.force

Look for this line: network.auth.force-generic-ntlm-v1

If the value = false double click on that line to change to 'True'

Please report back on results.

Toad-Hall said

Please try this: MAC 'Thunderbird' > 'Preferences' > 'Advanced' > 'General' tab click on 'Config Editor' button in top search type: auth.force Look for this line: network.auth.force-generic-ntlm-v1 If the value = false double click on that line to change to 'True' Please report back on results.

Ok changed the network.auth.force-generic-ntlm-v1 to 'True'

I seem to be able to send email, but I get the following error message: The was an errror saving the message to sent. Retry?

And also:

The current command did not succeed. The mail server fro account benn.coombes@cphart.co.uk responded: [TRYCREATE] Folder is not found.

But emails are getting to email addresses i am sending too.

Good to hear you can at least send emails.

Please check a couple of things: IMAP mail account 'Sent' folder is a subscribed folder and is displaying in the left Folder Pane.

'Tools' > 'Account Settings' > 'Copies & Folders' for the imap mail account. When sending messages, automatically: select : 'Place a copy in' select: 'Other' and choose the Sent folder on the imap mail account

Note: sometimes the imap mail account Sent folder can be called something similar eg: 'Sent Items'

click on OK

Thanks Toad-Hall, everything seems to be working correctly now and all sent mail is going into my sent mail folder.