Could you please send a log from the device.
Using IE or Chrome, go to the ip address of your device
Login as the admin
Scroll to the bottom of the Home page until you see the QuickLinks
Select the Support
Select Network Trouble Shooting
Clear the Log
Then select start session
Go to the device, and select the app and attempt to login. Once you get the issue you are describing you can then select the Stop Session
Download the session and send it to me via the private email.