Unable to send email using Apple (Mac) mail

I am unable to send email from my Mac mail program. Incoming mail works fine. When I look at server settings, it shows my account being offline under SMTP. If I attempt to reenter my info (password, etc.) I get a message that says" SMTP account already exists. Only a single SMTP account is allowed to be saved." I can send email using web mail in a browser. Using Mail 13.4, MacOS 10.15.5.