The report server cannot decrypt the symmetric key used to access sensitive or encrypted data in a report server database

"The report server cannot decrypt the symmetric key used to access sensitive or encrypted data in a report server database....." Everything was working well and one day saw this!

This can be fixed if you happen to have a backup of your encryption key If not, follow these steps:

Open Reporting Services Configuration Manager

Connect to your RS server

Select 'Encryption Keys' from the left pane

Press the 'Delete' button to get rid of your encrypted content

Close the Reporting Services Configuration Manager

Now your report server will work but if you check your reports they will not show data because when we deleted all the connection strings would be gone. So go to the data sources and set the connection string and now the reports will work.

Take a backup of the encryption because if you did have a backup, then press the 'Restore' button instead of the 'Delete' button in the Reporting Services Configuration Manager.