Google Services is missing

I hereby report that even after I have downloaded and re-inserted the Google-Services.Json file in my application, it still keeps issuing the following error at the time of its construction:

File google-services.json is missing. The Google Services Plugin cannot function without it.

The strange thing is that, a while ago the build was successful using the same google-services.json, and to make matters worse, I also removed the respective functions of firebase notifications, because, as I saw in the forum, this could be causing problems , however, even after removing GetDeviceToken, the error still persists!

What should I do?