Firebase Remote Config Fetch failed with user not authorized
After digging a little bit, and looking all over the place, I found that for some reason I had to go to https://console.developers.google.com -> Enable API and Services -> Firebase Remote Config, and enable that API. After doing that everything started to work again.
I hope this helps someone in the future, cheers!
I faced a similar issue in my Flutter project (it includes Android and iOS). On Android everything works fine (don't forget to add your debug SHA-1 in firebase settings) but on iOS I got the following error messages:
Runner[630:137105] 6.22.0 - [Firebase/RemoteConfig][I-RCN000026] RCN Fetch failure. Response http error code: 403
Runner[630:137105] 6.22.0 - [Firebase/Performance][I-PRF710001] Unable to fetch configurations.
Accepted answer by @eslimaf is correct but if Remote Config is already enabled you should try the comment by @cosic, it saved my day.
For those who struggle to find where to change those restrictions I'll add a few screenshots. All credits to @cosic
Go to https://console.developers.google.com
Open Credentials tab, open Android or iOS key in API Keys section
Check "Don't restrict key" or if you check "Restrict key" - make sure you've added all your services that you need.
Click SAVE, changes will take effect in a couple of minutes.
Hope this helps!