Hi,

So you are getting the access token correctly

But unable to use that.

Did you verify the access token is valid?

Did you check the API which you are consuming has any ACL attached?

check these links for help

https://community.servicenow.com/community?id=community_question&sys_id=bf4d8c391b59549017d162c4bd4b...

https://hi.service-now.com/kb_view.do?sysparm_article=KB0565021

Regards
Ankur

Regards,
Ankur
Certified Technical Architect  ||  10x ServiceNow MVP  ||  ServiceNow Community Leader