Cannot connect to Jira instance using Jira Data Center and Server mobile app

[erica_m_92]

Hello, I have installed the app Jira Data Center and Server on a phone but I cannot connect to my company's Jira. I am using the correct URL and the app is connected to my company VPN, but when I try to connect to the URL I get an error: impossible to connect to the site (It is possible that the URL is wrong, that it is necessary to use a VPN, or that Jira is not available).

I don't understand how to fix the problem, since the URL is correct, I am connected to the VPN and I am able to access Jira on the phone browser (with the VPN). 

Also, Jira Mobile is installed, and the Mobile Plugin for Jira is enabled under user installed apps.

What am I missing? Is something else that needs to be configured? 

Thanks a lot.