The ESM service is unable to connect to mailboxes when connecting though the CAS.
How to speed up process mailboxes.
How to speed up processing the journal mailbox,
The WLOGS may indicate Clock Skew or Generic MAPI errors.
The NLB is blocking or slowing down connections between Archive Manager and the CAS server.
1) Open a *.WLOG for a mailbox. WLOGS can be found under the Archive Manager ESM directory.
2) Take note of the CAS Array FQDN in the connection string entry, an example is below:
23:53:03 Connect string is 'server=ExchangeServer;mailbox=/o=First Organization/ou=Exchange Administrative Group (FYDIBOHF23SPDLT)/cn=Recipients/cn=user1;type=user;mode=mailbox;isservice=1;isHiddenFromGal=0;isExchange55=0;addPFFlags=1;notLastTry=1;serverDn=/o=First Organization/ou=Exchange Administrative Group (FYDIBOHF23SPDLT)/cn=Configuration/cn=Servers/cn=casarray.domain.com'
The CAS Array name above is casarray.domain.com
3) On the Archive Manager Services server, Click Start | Run and type c:\windows\system32\drivers\etc\hosts
4) Click OK.
5) Open the hosts file with notepad or a text editor.
6) Scroll to the bottom of the hosts file and input an IP address followed by the CAS Array name as found in step 2. An example of this is below:
192.168.10.10 casarray.domain.com
The line above will direct all requests to casarray.domain.com directly to a CAS server, bypassing any NLB's.
7) Click File | Save and close the hosts file.
8) Restart all Archive Manager Services.
