apple mail software not working since latest update for high sierra

just updated to 10.13.2 and now Mail is not accepting any of my email addresses - says it is not able to verify on my server but server is fine, passwords and user names are correct and all was working great until the latest update as well as many other problems. I realize I should know better than to update when they are first available but I run my business with these emails and can't contact communicate now. Help!