Replica check on secondaries

Good afternoon all,
I keep receiving every few minutes this warnings into the log:

W STORAGE [FlowControlRefresher] Flow control is engaged and the sustainer point is not moving. Please check the health of all secondaries.

What can I check to be sure that is not causing problem? Storage check? Replica check? Secondaries?

Many thanks in advance,

Flow control engaged means your secondaries can not catch up with write speed from primary node, and primary has to slow down, so you should check everything that may cause “slow replication”, including but not limited to disk use, network use, connection health…

Thank you. I have checked network performance and is okay.
Could you please provide some useful commands that I can run from mongo db perspective, please? For example db.printSecondaryReplicationInfo()
Thank you in advance