An application pool is a group of one or more URLs that are served by a worker process or set of worker processes. Application pools are used to separate sets of IIS worker processes that share the same configuration and application boundaries.
Solution: These two steps out of all steps listed below solved my issue.
1. Assign the right in the Local security group too and
2. Grant “Log on as Batch Job” permission to the application pool identity account
- The account used as application pool identity shouldn’t be locked - Reset the password of the application pool identity account in case it is expired - Switch from built-in account to domain account for application pool identity - Use another domain account as application pool identity - Give “Full Control” to application pool identity account on shared data and configuration folders - Give “Log on as Batch Job” permission to the application pool identity account - Add the application pool identity account to IIS_USRS group - Check account information in applicationHost.config for possible typos - Recreate application pools, websites, and shared configuration (if used) - Make sure to use the same encryption provider (IISWASOnlyCngProvider or IISCngProvider) in applicationHost.config - Change application pool process model from LogonBatch to LogonService - If it is a shared configuration setup in IIS, use the same IISWASKey