Unable to test connection via OAuth

Issue:

When I select Test Connection using Oauth as my authentication type, I get a 508 gateway error.

Solution:

The IP address for GridBuddy Connect needs to be allowlisted.

1. In Salesforce, go to Setup and then Login History to get the IP address for GridBuddy Connect that you need to allowlist.
2. Copy the Source IP in the row that has “Restricted IP” in the Status column and “GridBuddy Connect” in the Application column. This IP address will need to be added to your allowlist.

If you allowlist IPs at the Profile level under Login IP Ranges:

1. Go to Setup, then Profiles.
2. Select the name of the Profile.
3. Find Login IP Ranges and add a new entry with the same IP Start Address and IP End Address as the IP copied above. 

Note: As of 2021, GridBuddy Connect IPs are not static.