intermittent errors in Google Ads API

[sanpaku72]

Using the PHP client lib for Google Ads API here (googleads/google-ads-php v22). It seems there is an increased number of intermittent errors in Google Ads API:

• cURL error 60: SSL certificate problem: self signed certificate
• Resource has been exhausted (e.g. check quota).",
• Internal error encountered
  And also in oauth2.googleapis.com:
• Internal error encountered
• The service is currently unavailable
  The people at Google Ads API point to the client library. But the client lib is working fine; the errors are intermittent.
  Anything that can be done on the client end?