Error Code "OSC-CREST-00028" when using REST API

Content

Hello All,

I am getting "You are forbidden to access this site" when i using REST API but my code is working fine for a long time, suddenly it throws this error i don't know why. I refer lot of post related this but no solution. Can anyone help me

 

{
    "type": "https://test.custhelp.com/services/rest/connect/exceptions/OSC-CREST-00028",
    "title": "You are forbidden to access this site",
    "status": 403,
    "detail": "You are forbidden to access this site",
    "instance": "https://test.custhelp.com/services/rest/connect/v1.3/contacts/4",
    "o:errorCode": "OSC-CREST-00028"
}