For some reason, I started getting 403 errors on my app(in development), the errors message was
Access Not Configured. YouTube Data API has not been used in project XXXXXXXX....
This is weird because I was using the API for the last month or so with the same project, and didn't do any changes.
After looking in the project settings I noticed that the daily quota was reduced to 0.
The only thing concerning the API that I did was to request a quota increase in order to keep developing(The default quota stalled the dev on the search functionality of my app), but I didn't get any answer concerning that request other than asking for info, no warnings, or anything really.
I'm pretty sure that my app complies with the Terms of service, so I don't think that is the reason.
Any help would be appreciated. Thanks!
I would check your email it sounds like your project was disabled. Have you been though the verification process?
I would check your email. I have several emails about projects i no longer use which have had the quota reduced to 0 over the last few weeks.
How to reset
No matter what the clients you have now are not going to work you need to reset the project.