Can't Get Command Line/GUI Clients To Push To Repo - pre-receive hook declined

I’m running the community edition omnibus in Docker (network is macvlan). My client machines are all running Windows 10.

I’m sure this is a configuration error on my part, but for the life of me I cannot get “git push” to work either with the GitHub GUI (configured to talk to my local gitlab) or using the git command line tools.

I’ve created a SSH key that my gitlab installation accepted but pushes fail with either SSH or HTTP.

On gitlab, I have protected branches turned off for the repo I’m using to test.

The error I get is [remote rejected] main -> main (pre-receive hook declined)