HexousKoneko gave kudos to LesRMed in Eset Endpoint v8.1 LiveGrid connection problem
There is another topic with the same issue
We're experiencing the same issues since upgrade to 8.1. It's random as far as the users; some are remote users in another office or working from home, and some are here at our main office. Sometimes they resolve the issue on their own after a short period, some after a few days, but I have a couple of others that are still showing errors after about a week.
HexousKoneko gave kudos to Marcos in eM Client Email Protection
As long as you receive email via POP3/IMAP, received email will be scanned for threats without any additional configuration. if you receive email via POP3S/IMAPS and the email client doesn't honor the root CA certificates in the trusted root CA certificate store, you'll need to save the root CA certificate and import it in the email client CA certificate store manually.