It's my personal opinion that OAuth 2.0 came about primarily to address the mental anguish of developers who have struggled with OAuth 1.0.
The majority of the issues are probably related to improperly creating the signature, but there are a few lesser known and lesser documented issues.
If you're getting the overly vague "Could not authenticate with OAuth", these suggestions might help:
- Make sure that you're using the correct method (GET / POST). That is, make sure the method you are using is appropriate for the request your making and that it matches the method in the signature.
- Don't depend on a library for a given application to be 100% correct. It may be written for a specific use case, so you may need to do a little debugging.
- Check if your parameters need to be URL encoded.
- Verify that your parameters are in the correct order and have the correct case before being signed.
More specific troubleshooting can be found for the following services: