util/RfMail.cs

@@ -766,6 +766,9 @@ namespace rockfishCore.Util
             {
                 // Accept all SSL certificates
                 client.ServerCertificateValidationCallback = (s, c, h, e) => true;
+                //case 3667 fix for intermittent cert issue hopefully
+                //https://github.com/jstedfast/MailKit/issues/515#issuecomment-439438242
+                client.CheckCertificateRevocation = false;
                 //client.Connect(MAIL_IMAP_ADDRESS, MAIL_IMAP_PORT, true);
                 if (mirrorServer)
                     client.Connect(MAIL_MIRROR_IMAP_ADDRESS, MAIL_IMAP_PORT);