Sometimes the report labels do not show in reports or the report shows label IDs like Labels!@SYS2123 instead of label values.
There are two reasons to this type of issues:
You have moved your AX service account from AX domain account from AX domain admin group
You have changed your SSRS service account password.
Solutions:
1. From the Start menu, point to All Programs, click the SQL Server folder, click theConfiguration Tools folder, and then click Reporting Services Configuration Manager.
2. In Reporting Services Configuration Manager click Connect and then click Service Account.
3. Set the password and then click Apply. The account and password should be the same as the Microsoft Dynamics AX proxy account.
4. System will ask you to backup your encrytion key, and then will some settings on the backhand.
5. Now Click the ServerName/MSSQLSERVER on the left top of the reporting server and then click Stop. Then click Start to restart the server. Always check with the SQL administrator and make sure no other users are connected to the server before you restart the server.
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Now try opening your report again, your issue will be resolved.