E-mail not working

I just got back from out of town and my e-mail is not working. I checked all the settings and all seems fine. I tried to log in using web based client and rejected my password. I tried to change my password but no avail. I noticed that there have been some changes to the e-mail. is there something I need to fix? Thanks in advance.

I’m fuzzy on “not working.” Can you elaborate, with specific error messages or pop-ups from your mail client?

it just says that my password and username was not accepted. I know that my password is still what is used to be. I can change the password in CP and still can’t get in.