Create following policy.
Use Decode JSON Web Token Assertion
Return custom error if we receive malformed JWT request.
Do the folloing case
01. Results of normal JWT
02. Results when adding two or more letters to a normal JWT to make it into an incorrect JWT format
03. Results when deleting part of characters from normal JWT and making it into an incorrect JWT format
04. Results when adding one character to normal JWT to make it into an incorrect JWT format
01. Return 200 OK , Policy is successful
02. Return custom error , Policy is successful
03. Return custom error , Policy is successful
04. Return 500 error , Policy failed
Bug of API Gateway
API Gateway 9.0
The problem was solved v9.3.