“You can't view more than 5 calendars at once. To view this calendar, cancel your selection of another calendar”

We are migrating to Exchange 2013 and moved some mailboxes to Exchange 2013.

Now all of the sudden the test users that are on Exchange 2013 OWA are facing warning:

“You can't view more than 5 calendars at once. To view this calendar, cancel your selection of another calendar”

This warning occurs when they select more than 5 calendars in OWA where they have permissions on.

1)Is this adjustable and how ?

I know this is NOT adjustable with the OWAConcurrency setting in the throttlingpolicy

OWAMaxConcurrency :TheOWAMaxConcurrency parameter specifies how many concurrent connections an Outlook Web App user can have against an Exchange server at one time