[Solved] – 1 (one) Mailbox cannot Access More Than 16 Users

Posted: April 11, 2017 in Windows

I have error when user access email from Outlook Web Access (OWA) cannot access your mailbox, but other can used that. When I checked from event viewer, I found error below
Mapi session "5757391d-b61f-4393-9c2a-92c3922f203e: /o=First Organization/ou=Exchange Administrative Group (FYDIBOHF23SPDLT)/cn=Recipients/cn=claimsf30" exceeded the maximum of 16 objects of type "session".



  1. On the server that is running the Exchange Server 2010 Mailbox role, click Start, click Run, type regedit, and then click OK.
  2. Locate and then click the following key in the registry:
  3. On the Edit menu, point to New, and then click DWORD Value.
  4. Type Maximum Allowed Service Sessions Per User, and then press ENTER.
  5. On the Edit menu, click Modify.
  6. Type the decimal value that specifies the number of sessions that you want to use, and then click OK.
  7. Exit Registry Editor.

Note The registry value Maximum Allowed Service Sessions Per User affects all Mailbox Databases on the server and is not applied on a per-user basis. If you increase this value, server performance may be adversely affected. For example, doubling the number of service sessions from 16 to 32 could slow server performance.



CMIIW, Thanks Smile

Leave a Reply

Your email address will not be published. Required fields are marked *