For many months, I've successfully used Thunderbird to access all my eMail accounts including those on Gmail, Yahoo, and on my personal InMotionHosting account, www.LArents.biz. Two days ago, I suddenly could no longer send messages from either of my Win7 desktop machines. The most obvious problem is that I get an error message when saving an outgoing message as a draft or saving outgoing message to the sent-mail folder. I suspect it may be a result of a recent Microsoft update to my Windows7 machine. There is also the possibility that Norton 360 installed on both (all) machines could be troublemaker; I've noticed that Norton has significantly updated the "look" of their portal on Christmas Day '24. ''''''A new Thunderbird installation on my Win10 desktop machine seems to work just fine.''' ''' The Thunderbird settings appear identical between the Win10 and Win7 desktops, yet on the Win7 desktop I get messages like these: ''* "sending of the message failed. Peer's Certificate issuer is not recognized" * "Legitimate banks, stores, and other public sites will not ask you to do this. .Unknown Identity.. The certificate is not trusted because it hasn't been verified as issued by a trusted authority using a secure signature. '' Suggestions as to possible cause & solutions? Note main Win7 machine has quad processor, 16 GB of RAM, 500 GB SSD and Norton360 protection.