I keep getting the following error when my code tries to create a new data store in my custom big table. I have 10 nvarchar(max) columns available for data to be put into in that table so I have no idea why this is happening. Please see the stacktrace below:

System.InvalidOperationException: Could not map property MyProperty - table MyTable does not contain any columns that map to DbType.String
at EPiServer.Data.Dynamic.StoreDefinition.GenerateMappings(IEnumerable`1 typeBag, StoreDefinitionParameters parameters, Int32 version, IList`1 existingMappings, IDictionary`2 pendingRenames)
at EPiServer.Data.Dynamic.StoreDefinition.<>c__DisplayClass27_0.<InternalCreate>b__0()
at EPiServer.Data.Cache.Internal.LocalCache`2.Add(TKey key, Boolean cacheNullValues, Boolean overwriteExistingValue, Func`1 getAction, Action`2 setAction)
at EPiServer.Data.Cache.Internal.LocalCache`2.Add(TKey key, Boolean cacheNullValues, Boolean overwriteExistingValue, Func`1 action)
at EPiServer.Data.Dynamic.StoreDefinition.InternalCreate(String storeName, IDictionary`2 typeBag, StoreDefinitionParameters parameters)
at EPiServer.Data.Dynamic.Internal.EPiServerDynamicDataStoreFactory.CreateStore(String storeName, IDictionary`2 typeBag, StoreDefinitionParameters parameters)
at EPiServer.Data.Dynamic.Internal.EPiServerDynamicDataStoreFactory.CreateStore(String storeName, Type type, StoreDefinitionParameters parameters)