Connection has stopped syncing (400 error) - how do i work out why?

Hi Doppler friends!

I’ve run into a confusing issue where my sync has stopped working.

I’m running an app on digital ocean, pulling vars from Doppler (new process to me, I have to say i love it!)

I’ve just added two additional vars, and then i got a ‘400’ error and my sync was disabled.

I’ve tried removing the vars, creating a new sync, however the situation hasn’t resolved and i’m not sure what to do next.

Any guidance on what i should do from here?

Thanks
Brad