Exchange 2016 wont send/receive- Microsoft.Exchange.Data.Storage.NoInternalEwsAvailableException

[EkontosWDB]

I am receiving the following errors:  

Microsoft.Exchange.Data.Storage.NoInternalEwsAvailableException: No internal Exchange Web Service URL is available for mailbox 

'LegacyDn: /o=XXXXX /ou=Exchange Administrative Group (FYDIBOHF23SPDLT)/cn=Recipients/cn=537232308af0417bba21a42b76358c14-SystemMailb, RecipientType: UserMailbox, RecipientTypeDetails: ArbitrationMailbox, Selected Mailbox: Display Name: Microsoft Exchange, Mailbox Guid: 16967a0c-02ef-4483-a56e-b5cbb1109a9e, Database: 9795f754-54dc-4de8-8e60-03ed1deb3784, Location: ServerFqdn: XXXX.XXXX.XXX, ServerVersion: 1942063364, DatabaseName: MB DB Exch 2K16 8-2-21, HomePublicFolderDatabaseGuid: 00000000-0000-0000-0000-000000000000'

Can't find any information on how to resolve the problem.  Recently moved mailboxes from one database to another but has been working fine for several weeks since then.

[#2]

Please make sure you have your arbitration mailboxes active.
Get-Mailbox -Arbitration | ft name,database