Error Got Http response code 401 when accessing https://api.paypal.com/v1/oauth2/token.

[MANJUDEVI999]

Error Got Http response code 401 when accessing https://api.paypal.com/v1/oauth2/token. Please solve this problem immediately

[MTS_Chiranjeevi]

Good day @MANJUDEVI999,

Thank you for posting to the PayPal community.

Reported "401 error/Invalid Token" /"invalid_client"/"Client Authentication Failed" usually occurs if there is an issue with the REST API credentials you're attempting to use or you're attempting to use REST API credentials for our sandbox environment within our production environment or vice-versa.
 
I would suggest to please cross check the API credentials and valid for the environment where you're submitting the request.  

Each REST application contains a set of both sandbox and production API credentials, with the sandbox credentials being shown by default. 

Guide link - https://www.paypal.com/us/cshelp/article/how-do-i-create-rest-api-credentials-ts1949 

Sincerely,

Chiranjeevi

PayPal/Braintree MTS

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