All exchange datastore is selected, but one database is backed up

Hello,

I've juste installed a new server for backup with BE2014 (i ran 2010R3).

For my backup to tape job, i've selected all of the datastore, but when i saw the result this morning, just one database were backed up.

Remote's agents stayed in 2010R3 and i've got Exchange 2010 SP3.

Have you got any idea?

Thank you.