Why am I getting this error "Could not contact master. Check that the master is up, the master_uri=https://xx.xxx.xxx.xxx:8089 and secret are specified correctly"?

[vikramyadav]

I have updated my Cluster Master and it says to check the master and giving me an error.

[woodcock]

Usually this is a firewall problem. There might be a firewall in your network of on forwarder blocking this traffic.

[richgalloway]

Have you looked at http://docs.splunk.com/Documentation/Splunk/7.1.0/Indexer/Enablethepeernodes?

[vikramyadav]

Currently I,m working on a standalone license server, but i tried to make this server as a slave but its gives me following error

Splunkd daemon is not responding: ("Error connecting to /services/licenser/localslave/license: ('The read operation timed out',)",)

I want to Designate a different Splunk instance as the master license server and even i had setup master mode.
please find attachment.