Cannot connect after changing ISP/Mobile Data

Hello Everyone ,

My problem is that, when I use another ISP or mobile data I get timed-out trying to connec VPN.

If I am connected to my regular ISP, I can connect directly I can even ping the IP however if I will use another ISP i am unable to connect to our VPN client.

Please advise as I am really having struggles lately because whenever the main ISP will be down due to maintenance I cannot continue working using the backup mobile data.

Thank you.