Connection Timed Out (0x0000274c/10060)

We a re setting up a POC for a nonprofit. The Postgres 10.6 instance has been running since June with no problems. There was a period of about three weeks where no one accessed the instance. In the last few days, we have made multiple attempts to access the instance from multiple sites. Each attempt has resulted in the same error as listed in the subject line. The documentation stated that this was most likely an authentication failure, suggesting to attempt to connect to the end point via a telenet session, if successful it would prompt for username and password. However, the telenet session also fails to connect. I can find no other causes for this error, any ideas?

Thanks in advanced for all the efforts
Bill