Mail quit sending on Laptop

I'm stumped. Using MacBook Air M2 2022 IOS Sonoma 14.7.2. For several days now Mail will not send. My iPhone & iPad both send mail fine but laptop keeps saying "Mail wants to sign using key 'privateKey" in your keychain. To allow this, enter the "login" keychain password." I have tried all of the suggestions I can find. I can't find a login keychain password listed anywhere nor can I find any mail passwords at all listed in my keychain listings. I don't know why it says mail wants to 'sign' other than maybe it is trying to encrypt my mail which I did not set up as far as I know.Mail will not send. Also the message window remains one the screen even after I close mail. I have to restart laptop to make it go away.