It might be due to commvault Firewall Configuration.
On the remote MA configure as per below:
Entity = <Proxy Server>
State = <RESTRICT>
Remote Entity = <The clients or MA you'd like that this MA talk to, you may need to create a client group>
Route Type = Via Proxy
Remote proxy = <Proxy Server>
Not sure if have 2 proxies (one for the DMZ and another for your main subnet).
If you have 2 proxies, you need to go to the DMZ proxy and also configure it to just talk to the proxy in your main network, such as.
Remote Entity: <commserve> <media agents>
Route type: Via proxy
Proxy settings: <the proxy on the main network>
The tunnel HTTP/HTTPS port is 8403.
Always push firewall configuration after a firewall conf change
Run the cvfwc_ping command to test connectivity to the client computer.
For troubleshooting you can check the cvfwd log file.
Fort further information regarding firewall configuration please navigate to.
I hope it helps :)