I have a problem which resembles the above. Unfortunately, the latest version does not seem to resolve this. I have now rolled back to 4.85.
I have seen this only with one e-mail provider, zonnet.nl. Furthermore, in the mainlog I get:
2015-10-13 20:18:55 1Zm49y-0007pC-04 [217.149.195.27] SSL verify error: depth=0 error=self signed certificate cert=/C=NL/ST=Some-State/O=InterNLnet / Tele2/OU=IT/CN=deliver01.zonnet.isp-net.nl
2015-10-13 20:18:55 1Zm49y-0007pC-04 [217.149.195.27] SSL verify error: certificate name mismatch: "/C=NL/ST=Some-State/O=InterNLnet / Tele2/OU=IT/CN=deliver01.zonnet.isp-net.nl"
2015-10-13 20:18:56 1Zm49y-0007pC-04 Spool file 1Zk7W3-0005kF-Rt-D not found
Could the SSL error have anything to do with this?