I am running 2.2.2 with GP Premium 1.8.2 on WordPress 5.2. For some reason the Site Library is not showing up, although I recall it working in the past. Query Monitor indicates a cURL error 7.
Here is the full output of Query Monitor:
Method GET
URL https://gpsites.co/wp-json/wp/v2/sites?per_page=50
Status cURL error 7: Failed to connect to gpsites.co port 443: Connection refused
Caller generatepress_sites_init()
Component Plugin: gp-premium
Timeout 5
Time 1.0090