NBU status: 96, EMM status: No media is available unable to allocate new media for backup, storage unit has none available (96)

Hello All..We are getting error  only on big sized policy  after a 3-4 hours

NBU status: 96, EMM status: No media is available
unable to allocate new media for backup, storage unit has none available  (96)

For example now we started the policy with 5TB .Now it is normal . But  after 3-4 hour it will give error again.

But we have 185 available media,

We a using Fujitsu VTL.

With BR,

Turgunbek