Welcome to the Community Forum and thanks for your post. I'm sorry to hear that you are experiencing a problem with the Virgin Mobile My Account app. Has this issue been resolved for you since your post?
If you are still getting the connection error, please go through the following checks and get back to me with these results:
Are you able to access websites via your mobile internet connection (with WiFi off)?
Are you able to access websites via WiFi on your handset (with mobile data off)?
Are you able to log into the Virgin Mobile Your Account website and access your mobile bill?
Does the app work if you have the handset WiFi off and the mobile internet on?