My wife and I have been having problems with Thunderbird since the last operating system update to our Mac OS. Here is the problem: • Sometimes we are unable to send an outgoing email. Other times, we are able to send messages normally. • When sending fails, the message which is returned to each of us is the following: Sending of the message failed. The outgoing server (SMTP) smtpauth.earthlink.net does not seem to support encrypted passwords. If you just set up the account, try changing the ‘Authentication method’ in Account settings Outgoing server (SMTP) to ‘Normal password’. • Changing the setting according to the instructions in the above message does not fix the problem. • We each have Apple iMac computers Hers is an iMac Retina 27-inch, 2017 Mine is an iMac 21.5-inch, 2017 • Both computers have Mac OS Big Sur version 11.4 installed • This problem did not exist prior to the last OS update. • Neither computer has any antivirus software innstalled. • The conclusion is there appears to be a conflict between the current version of Thunderbird (78.10.2) and Big Sur version 11.4. Do you have a fix for this problem? Doing a restart in the Safe Mode followed by a normal restart seems to temporarily correct the problem. Thank you for any help you can provide.