Can't Get Or Set Achievements With Steamworks.NET

I'm using Steamworks.NET to set up Steam ac$$anonymous$$evements in the game I'm working on. The SteamManager is initialising properly, the App ID is properly set and the ac$$anonymous$$evements have been published. Calling GetAc$$anonymous$$evement however, returns false. SetAc$$anonymous$$evement has the same problem and the UserAc$$anonymous$$evementStored_t callback is never called. All of the other calls to the Steamworks API return true and their callbacks are triggered with no errors.

Any ideas as to why these calls are returning false or anyt$$anonymous$$ng else to check would be appreciated.

Here's my code:

 public class SteamAc$$anonymous$$evementManager : Ac$$anonymous$$evementManager
 {
     List<Ac$$anonymous$$evementID> ac$$anonymous$$evementQueue = new List<Ac$$anonymous$$evementID>();
     List<Ac$$anonymous$$evementID> backupAc$$anonymous$$evementQueue = new List<Ac$$anonymous$$evementID>();
 
     private Callback<UserStatsReceived_t> statsRequestedResult;
     private Callback<UserStatsStored_t> statsStoredResult;
     private Callback<UserAc$$anonymous$$evementStored_t > ac$$anonymous$$evementStoredResult;
 
     bool awarding = false;
 
     int retryCount = 0;
     int maxRetryCounts = 5;
 
     public override void Init()
     {
         if( !SteamManager.Initialized )
         {
             Debug.LogError( "Tried to Init SteamAc$$anonymous$$evementManager but SteamManager is not initialised" );
             return;
         }
 
         //Steamworks.SteamUserStats.ResetAllStats( true );
 
         statsRequestedResult = Callback<UserStatsReceived_t>.Create( OnStatsReceived );
         statsStoredResult = Callback<UserStatsStored_t>.Create( OnStatsStored );
         ac$$anonymous$$evementStoredResult = Callback<UserAc$$anonymous$$evementStored_t>.Create( OnAc$$anonymous$$evementStored );
 
         SteamUserStats.RequestCurrentStats();
     }
 
     public override void AwardAc$$anonymous$$evement( Ac$$anonymous$$evementID ac$$anonymous$$evementID )
     {
         if( !SteamManager.Initialized )
         {
             Debug.LogError( "Tried to Award Ac$$anonymous$$evement but SteamManager is not initialised" );
             return;
         }
 
         ac$$anonymous$$evementQueue.Add( ac$$anonymous$$evementID );
         if( !awarding )
             AttemptToAwardAndStoreAc$$anonymous$$evements();
     }
 
     void AttemptToAwardAndStoreAc$$anonymous$$evements()
     {
         awarding = true;
 
         if( SteamUserStats.RequestCurrentStats() )
         {
             Debug.Log( "Successfully Requested Stats" );
         }
         else
         {
             Debug.LogError( "Failed to Request Stats" );
             CompleteAwarding( false );
         }
     }
 
     void OnStatsReceived( UserStatsReceived_t result )
     {
         if( result.m_eResult != EResult.k_EResultFail )
         {
             Debug.Log( "Successfully Received Stats " + result.m_eResult );
             AwardQueuedAc$$anonymous$$evements();
         }
         else
         {
             Debug.LogError( "Failed To Received Stats" );
             CompleteAwarding( false );
         }
     }
 
     void AwardQueuedAc$$anonymous$$evements()
     {
         List<Ac$$anonymous$$evementID> ac$$anonymous$$evementsToAward = new List<Ac$$anonymous$$evementID>( ac$$anonymous$$evementQueue );
 
         w$$anonymous$$le( ac$$anonymous$$evementQueue.Count > 0 )
         {
             Ac$$anonymous$$evementID ac$$anonymous$$evementID = ac$$anonymous$$evementQueue[ ac$$anonymous$$evementQueue.Count - 1 ];
             string steamID = Ac$$anonymous$$evementData.ac$$anonymous$$evementList.GetAc$$anonymous$$evement( ac$$anonymous$$evementID ).steamID;
             bool alreadyAwarded;
             Debug.Log( Steamworks.SteamUserStats.GetAc$$anonymous$$evementDisplayAttribute( steamID, "name" ) );
             if( !Steamworks.SteamUserStats.GetAc$$anonymous$$evement( steamID, out alreadyAwarded ) )
             {
                 Debug.LogError( "Failed To Get Ac$$anonymous$$evement: " + steamID );
             }
             if( !alreadyAwarded )
             {
                 if( Steamworks.SteamUserStats.SetAc$$anonymous$$evement( steamID ) )
                 {
                     Debug.Log( "Awarded Ac$$anonymous$$evement: " + steamID );
                 }
                 else
                 {
                     Debug.LogError( "Failed To Awarded Ac$$anonymous$$evement: " + steamID );
                     backupAc$$anonymous$$evementQueue.Add( ac$$anonymous$$evementID );
                 }
             }
             ac$$anonymous$$evementQueue.RemoveAt( ac$$anonymous$$evementQueue.Count - 1 );
         }
 
         SetStats();
     }
 
     private void OnAc$$anonymous$$evementStored( UserAc$$anonymous$$evementStored_t result )
     {
         Debug.Log( "Ac$$anonymous$$evement Stored Callback" );
     }
 
     public void SetStats()
     {
         SteamUserStats.StoreStats();
     }
 
     private void OnStatsStored( UserStatsStored_t result )
     {
         if( result.m_eResult != EResult.k_EResultFail )
             Debug.Log( "Ac$$anonymous$$evement Stats Succesfully Stored" );
         else
             Debug.LogError( "Ac$$anonymous$$evement Stats Failed To Store" );
 
         CompleteAwarding( result.m_eResult != EResult.k_EResultFail && backupAc$$anonymous$$evementQueue.Count == 0 );
     }
 
     void CompleteAwarding( bool wasSuccesful )
     {
         awarding = false;
         retryCount = wasSuccesful ? 0 : retryCount + 1;
         ac$$anonymous$$evementQueue.AddRange( backupAc$$anonymous$$evementQueue );
         backupAc$$anonymous$$evementQueue.Clear();
 
         if( retryCount > maxRetryCounts )
         {
             Debug.LogError( "Failed to Award Ac$$anonymous$$evements After Multiple Attempts" );
             retryCount = 0;
         }
         else if( ac$$anonymous$$evementQueue.Count > 0 )
         {
             retryCount++;
             AttemptToAwardAndStoreAc$$anonymous$$evements();
         }
     }
 }