Mac Mail suddenly won't connect to outgoing smtp server
About every two months my mac mail will not connect to my email smtp server. If I open up Accounts all of the login and server info in Outgoing Mail Server (SMTP) is correct. Sometimes, if I delete the smtp account and rebuild it it will work... but not always. It seems like the Mail client is not actually using the data that is entered into the fields in the smtp account manager in the client. Really inexplicable. Please help before I have to switch to another client.
MacBook, macOS 10.12