I installed Avast two days ago to run a system scan and yesterday I found that Apple Mail, with an account hosted by mail.com that has been connecting for years, was unable to connect to the imap server. Restarting did not work, nor did deleting messages and emptying the trash on the server as well as on the Mac itself (in case it was the number of messages in inbox). Finally, I uninstalled Avast and immediately, Apple Mail is able to connect again.
Is there a fix?
In case it helps, here is a sample from the Console's log:
10/3/17 10:30:32.115 AM Mail[6955]: CFNetwork SSLHandshake failed (-9806)
10/3/17 10:30:32.709 AM com.avast.proxy[1463]: Defective IMAP request!
10/3/17 10:30:32.709 AM com.avast.proxy[1463]:
10/3/17 10:30:32.710 AM Mail[6955]: CFNetwork SSLHandshake failed (-9806)
10/3/17 10:30:54.860 AM com.avast.proxy[1463]: SSL_accept(): Connection reset by peer
10/3/17 10:31:32.134 AM com.avast.proxy[1463]: Defective IMAP request!
10/3/17 10:31:32.134 AM com.avast.proxy[1463]:
10/3/17 10:31:32.135 AM Mail[6955]: CFNetwork SSLHandshake failed (-9806)
10/3/17 10:31:32.714 AM com.avast.proxy[1463]: Defective IMAP request!
10/3/17 10:31:32.714 AM com.avast.proxy[1463]:
10/3/17 10:31:32.715 AM Mail[6955]: CFNetwork SSLHandshake failed (-9806)
10/3/17 10:31:33.275 AM com.avast.proxy[1463]: Defective IMAP request!
10/3/17 10:31:33.275 AM com.avast.proxy[1463]:
10/3/17 10:31:33.276 AM Mail[6955]: CFNetwork SSLHandshake failed (-9806)
10/3/17 10:31:33.850 AM com.avast.proxy[1463]: Defective IMAP request!
10/3/17 10:31:33.850 AM com.avast.proxy[1463]:
10/3/17 10:31:33.851 AM Mail[6955]: CFNetwork SSLHandshake failed (-9806)
10/3/17 10:32:32.129 AM com.avast.proxy[1463]: Defective IMAP request!
10/3/17 10:32:32.129 AM com.avast.proxy[1463]:
10/3/17 10:32:32.130 AM Mail[6955]: CFNetwork SSLHandshake failed (-9806)
10/3/17 10:32:32.730 AM com.avast.proxy[1463]: Defective IMAP request!
10/3/17 10:32:32.730 AM com.avast.proxy[1463]:
10/3/17 10:32:32.732 AM Mail[6955]: CFNetwork SSLHandshake failed (-9806)
10/3/17 10:32:33.357 AM com.avast.proxy[1463]: Defective IMAP request!
10/3/17 10:32:33.357 AM com.avast.proxy[1463]:
10/3/17 10:32:33.358 AM Mail[6955]: CFNetwork SSLHandshake failed (-9806)
10/3/17 10:32:33.918 AM com.avast.proxy[1463]: Defective IMAP request!
10/3/17 10:32:33.918 AM com.avast.proxy[1463]:
10/3/17 10:32:33.918 AM Mail[6955]: CFNetwork SSLHandshake failed (-9806)
