When starting MongoDB Ops Manager version 1.8.2.312, we have this error:

Migrate MMS data
Running migrations…[  OK  ]
Start MMS server
Instance 0 starting……….[  OK  ]
Start Backup HTTP Server
Instance 0 starting…….[FAILED]
instance: 0  – msg: unable to create new native thread

Solution: Increase the max number of process for user mongodb-mms:

$ sudo vi /etc/security/limits.d/90-nproc.conf

mongodb-mms     soft    nproc     unlimited