On-premise proxy errors during early morning maint. windows

I’ve never had issues receiving authorized grants at any point except during scheduled maintenance windows between 3-4am. We use on-prem with Google SAS. Last couple times we needed to schedule frequency changes at 4am, it has failed with “cannot connect to proxy”. Never have issues at any other time.

Is there a time-frame (window) in which On-prem and Google cannot process registrations?