Synchronizing folder list failed due to the following error: The SMTP address has no mailbox associated with it.

I have several accounts set up in eM Client.

3 Gmail accounts for Email (one of which is also for Contacts and Calendar)
1 Exchange account for Tasks syncing

My Exchange account is my Windows Live account linked to my primary Google email address (so I don’t actually use email in Outlook).

Everything was working fine until a few weeks ago. Now I get error messages every 10 minutes.

The listed Error is:

An error occured**.**
Synchronizing folder list failed due to the following error: The SMTP address has no mailbox associated with it.

The Log for each time stamp follows:

12:34:14 PM   MailClient.Storage.Application.OperationException: Synchronizing folder list failed due to the following error: The SMTP address has no mailbox associated with it. —> Microsoft.Exchange.WebServices.Data.ServiceResponseException: The SMTP address has no mailbox associated with it.
12:34:14 PM    at Microsoft.Exchange.WebServices.Data.ServiceResponse.InternalThrowIfNecessary()
12:34:14 PM    at Microsoft.Exchange.WebServices.Data.MultiResponseServiceRequest`1.Execute()
12:34:14 PM    at Microsoft.Exchange.WebServices.Data.ExchangeService.SyncFolderHierarchy(FolderId syncFolderId, PropertySet propertySet, String syncState)
12:34:14 PM    at MailClient.Protocols.Exchange.ExchangeFolderSynchronizer.GetFolderList(Folder homeFolder, CancellationToken cancellationToken)
12:34:14 PM    at MailClient.Protocols.Common.FolderSynchronizer.<>c__DisplayClass10_0.b__0(WorkerStatus status, CancellationToken cancellationToken)
12:34:14 PM at MailClient.Protocols.Exchange.ExchangeGenericCommand.Execute(WorkerStatus status)
12:34:14 PM — End of inner exception stack trace —
12:34:14 PM at MailClient.Protocols.Exchange.ExchangeGenericCommand.Execute(WorkerStatus status)
12:34:14 PM at MailClient.Commands.Command.Process(WorkerStatus status)
12:35:03 PM Outlook [Exchange Web Services] Synchronizing folder list
12:36:03 PM Outlook [Exchange Web Services] Synchronizing folder list
12:37:04 PM Outlook [Exchange Web Services] Synchronizing folder list
12:38:03 PM Outlook [Exchange Web Services] Synchronizing folder list

I checked the Settings to see if there was a way to simply disable Email syncing while retaining the Tasks/Calendar syncing with the Exchange account, but it appears to be an all or nothing account type.

I started using the Exchange Account option instead of the Outlook option several months ago due to a known bug with Reminder times not synching properly using the latter. Once I made that change, everything was working flawlessly until a few weeks ago (I don’t remember the exact date as I let this continue for several days assuming it was a bug that was added with a version update and would subsequently be fixed).

Thank you for any ideas you may have in helping me resolve this issue. It isn’t impacting things, just an annoyance that I have to constantly clear an error log.

Unfortunately Exchange accounts with outlook.com only provide two options for syncing tasks; EWS and EAS. With your account setup as Exchange in eM Client, that uses EWS, or Exchange Web Services. This is the only real option available on computers. And you are correct, it is an all-or-nothing option. The other option, as you had previously setup when using IMAP, was EAS, or Exchange ActiveSync. This is actually a mobile protocol, but somehow eM Client uses it when the account is setup as IMAP. 

Did you maybe update eM Client, and that is when this EWS error showed up?

If you are using the latest version of eM Client available for download at http://www.emclient.com/release-history, you could try going back to the Outlook option, and see if the reminder times are now working using EAS. 

Or, unless someone has a better idea, why not move your tasks to Google, as you are already using that?

I do not recall recently updating eM Client. I wasn’t sure if it rolled out updates in the background like Chrome does.

As for using Google for Tasks. Unfortunately, Google’s handling of tasks is awful right now. A features as simple as requesting a Reminder notification will not sync from eM Client to Google Calendar, and any changes made from, say my phone or online, conflicts when it tries to sync back to eM Client.

The easy solution was to just use Outlook (Exchange) and use Microsofts Tasks & Notes app on Android to provide the reliable and feature-rich task syncing between my desktop and mobile platforms.

As I mentioned. All was working fine until very recently (one or two weeks, I can’t provide an exact time) when that error starting popping up with every eM Client sync.

The other option, if you have a Pro License, is to open a support ticket with eM Client. By analyzing the EWS logs, they should be able to find the cause of the error.

Don’t know why that didn’t occur to me in the first place.

Thank you for your help!