If SSRS breaks in your on-premise SharePoint installation, update the password in the following areas in Central Admin:
1. Central Admin > Execution Account > SSRS Service
2. Central Admin > System Settings > SSRS Service

Things to check:

Execution account plus the password

Must be changed when passwords on the servers are updated

Makes integrated security work

Don’t change default settings

For troubleshooting, temporarily turn on Remote Errors

Sometimes STIGs or IA rules require turning off connection errors

Microsoft Access Services uses SSRS in the background