I'm completely baffled, and I hope this is the right place to come for help.
I"m running my own server, Windows 2016, and running hmailServer - not sure what version. It's running behind a netgear WNDR4500 router and wifi.
About 2 days ago, it appears to have simply stopped receiving email from anywhere except inside the local network. I double checked the port mappings in the router, because it was almost acting like the traffic wasn't getting through. I've sent myself email from gmail, and examined the logs, and don't see any indication that it ever connects.
It does look like there may have been some attempt to hack into it - I saw in the logs yesterday a large number of authentication failed messages, and also a lot of attempts to send email to practically every conceivable user name at one of my domains. But I couldn't see any indication that it caused any damage (except, of course, for not receiving any email.)
I'm not sure what else to look for. I've stopped and restarted the hmail server several times, and rebooted the whole server at least once. Also, because of having a residential IP address, I relay my outbound email through sendgrid. That seems to have stopped working, with an error message of taking too long to connect. I don't know if the problems are related or not, but it's suspicious.
Can anyone help me? Thanks.