There was a connection issue on July 10th, but it's back up now. When EVPN was first released as a beta, there were similarly a handful of connection issues.Thismost recent outage has been the only outage of any consequence for over a year. On the whole, the EVPN connection has been very, very reliable.
It is possible that you are just very unlucky and tried it during two rare outages. I use EVPN day in and day at work and at home and. other than the other day, it has been faultless for me.
I'd suggest you give it another try and yes, it does work on Win7.