Hey @pb_zoom, @josharcher,
Our engineering team is aware of the issue and investigating this. While the team is yet to confirm the exact cause of error, upon initial review, they suspect the issue lies with this specific use of the state parameter. In the meantime they have advised that you revise the OAuth URL to not use a state parameter and it should resolve the authorization error.
For a quick resolution, if you still plan to use the state parameter you can try either of these options.
Option 1:
If possible please limit to using a single value in the state parameter.
https://zoom.us/oauth/authorize?response_type=code&client_id=CLIENT_ID&redirect_uri=REDIRECT_URL&state=STATE_STRING
Option 2:
Make use of the base64UrlEncode or base64Encode function to encode the state parameter
https://zoom.us/oauth/authorize?response_type=code&client_id=CLIENT_ID&redirect_uri=REDIRECT_URL&state=BASE64_ENCODED_STRING
The engineering team is investigating this at priority and we will keep you updated on the status. Let me know if neither of these help resolve the error you are encountering.
Thanks,
Tommy