Possible Causes & Fixes:
1) Exceeded Daily Quota:
Check your Google Ads API quota usage in the Google Cloud Console.
Request quota increases if necessary.
2) Too Many Requests in a Short Period:
Implement exponential backoff to retry failed requests with increasing wait times.
Reduce API request frequency by batching operations.
3) Insufficient API Tokens:
Ensure OAuth2 tokens are valid and properly scoped.
Optimize API calls, monitor quotas, and use batch processing when possible.