Why am I getting a 503 Service Temporarily Unavailable error?

I have a new WordPress site (Ashe Pro theme) hosted on Lightsail (using the Lightsail load balancer). Everything was working fine for a couple of months and then suddenly I received a "503 Service Temporarily Unavailable" Error. It went away on its own after several days. Now it's back again.

I have no idea where to even start troubleshooting. Is there documentation somewhere and troubleshooting steps? Or can and get support from a human? lol.

Thank you.

Edited by: JodyJ on Jun 25, 2021 9:47 AM

Edited by: JodyJ on Jun 25, 2021 9:48 AM