Category Archives: SSRS

AX 2012, SSRS error: There was an error while trying to deserialize parameter

There was an issue we came across today where the users were not able to run any report on AX client and were getting the below error;

“The formatter threw an exception while trying to deserialize the message: There was an error while trying to deserialize parameter The InnerException message was ‘Element ‘’ contains data from a type that maps to the name ‘’. The deserializer has no knowledge of any type that maps to this name. Consider using a DataContractResolver or add the type corresponding to ‘SRSQueryBuilderArgs’ to the list of known types – for example, by using the KnownTypeAttribute attribute or by adding it to the list of known types passed to DataContractSerializer.’. Please see InnerException for more details”.

 This happens quite frequently when AOS serving the reporting server crashes, or someone restart the AOS server without ending client user sessions.


To overcome this problem and to make things straight, kindly follow the below steps;

  1. Manually end client’s session,  AX> System Admin > Users> Online user> End session.
  2. Stop AOS.
  3. Open SQL, Select the record from SysClientSessions, take the backup of the records just to be on a safe side.
  4. Delete all the records from SysClientSessions table from the databse.
  5. Restart SSRS services
  6. Start AOS

This should resolve your problem.. 🙂