IdentityServer4 -Connect/token API - getting an exception once a day

Question

We are using connect/token - IdentityServer4 in our application to generate the Auth token. We have allowed to request more than 1.5L time of request per month it is most often failed once a day, in particularly it failed in once a day sporadically in diffrent time.The Application gateway timeout is set to 120s, if we didn't get response in 120s this call will get timeout. So in this moment we found this Idenetity server take more than 2 mins to generate the token,even it is take less the 10 as average time to generate the response.

We looked at the Azure moniter at the failing moment and we have observered:

1. There is no SNAT port exhaustion during that time period
2. We don't see any abnormality like CPU, Memory from the AKS side.
3. We have checked DB connectivity and DTU all are looks very normal at the time of the failure.

Can someone please advise on how to over come this issue?

Yusuf