During last one or two months, I found some of my accounts are sending spam. Initially this happened to one or two accounts. But now a days, this is frequent. Every day one or more accounts falls prey for this. Then I changed http to https and the problem resolved for one week. Then yesterday I again found one more account sending spam. Also the server seems very slow when I changed to https.
During my observation, most of the mails were send during night time.(According to time stamp). I stopped Imap and pop3.
Kindly advise me how to tackle this problem.