Exchange ActiveSync has shut down because an unexpected critical error occurred

Hi, 

At one point all phones stopped syncing and when checking event log i came to this error:

Exchange ActiveSync has shut down because an unexpected critical error occurred.

URL=

--- Exception start ---
Exception type: System.OutOfMemoryException
Exception message: Insufficient memory to continue the execution of the program.
Exception level: 0
Exception stack trace:    at Microsoft.Exchange.Data.Storage.GenericListData`2.DeserializeData(BinaryReader reader, ComponentDataPool componentDataPool)
   at Microsoft.Exchange.AirSync.DeviceBehaviorData.DeserializeData(BinaryReader reader, ComponentDataPool componentDataPool)
   at Microsoft.Exchange.Data.Storage.DerivedData`1.DeserializeData(BinaryReader reader, ComponentDataPool componentDataPool)
   at Microsoft.Exchange.Data.Storage.GenericListData`1.DeserializeData(BinaryReader reader, ComponentDataPool componentDataPool)
   at Microsoft.Exchange.Data.Storage.GenericDictionaryData`3.DeserializeData(BinaryReader reader, ComponentDataPool componentDataPool)
   at Microsoft.Exchange.Data.Storage.SyncState.DeserializeSyncStateTable(Int64 idxTable)
   at Microsoft.Exchange.Data.Storage.SyncState.Deserialize(PropertyDefinition property)
   at Microsoft.Exchange.Data.Storage.SyncState.Load(Boolean reloadFromBackend, PropertyDefinition[] additionalPropsToLoad)
   at Microsoft.Exchange.Data.Storage.SyncState..ctor(SyncStateStorage syncStateStorage, StoreObject storeObject, SyncStateInfo syncStateInfo, Boolean syncStateIsNew)
   at Microsoft.Exchange.Data.Storage.CustomSyncState.GetSyncState(SyncStateStorage syncStateStorage, Folder syncStateParentFolder, SyncStateInfo syncStateInfo, StoreObjectId storeObjectId)
   at Microsoft.Exchange.Data.Storage.SyncStateStorage.GetCustomSyncState(SyncStateInfo syncStateInfo)
   at Microsoft.Exchange.AirSync.GlobalInfo.LoadFromMailbox(MailboxSession mailboxSession, SyncStateStorage syncStateStorage, ProtocolLogger protocolLogger)
   at Microsoft.Exchange.AirSync.Command.OpenSyncStorage(Boolean shouldOpenGlobalSyncState, Boolean shouldUseBudget)
   at Microsoft.Exchange.AirSync.Command.WorkerThread()
--- Exception end ---

mail server has 35GBs of Ram, plenty of disk space, no extra transaction logs adding or anything like that. Right now phones work, but every other minute that error pops up and after sometime event 1013 is logged saying that Exchange activesync has been loaded.

Thanks