iPhone authentication via the Network Agent auto-disconnects

Setup

• Sophos XG v17.0.0 GA

• iPhone 6 w/ iOS v8.x
  • iPhone auto-lock = disabled
  • iPhone sleep = disabled

• Sophos Network Client v1.2.6
  • Save Password = enabled
  • Auto Login = enabled

Issue

Despite the above settings, the Network Agent auto-disconnects within 1-3 minutes.

Procedure

1. Confirm the correct iPhone & Network Agent settings listed above under Setup.
2. Open the Network Agent app.
3. Verify the app has logged in - if not, then manually login.
4. Switch to Safari and attempt to browse.  Confirm web page loads properly.
5. Wait at 1-3 minutes.
6. If the iPhone is still awake, continue - if not awake, then restart the procedure.
7. Attempt to browse a different web page.
8. The desired page should not load and instead, the Sophos Captive Portal page should be presented instead.

Logs

• The pertinent logs can be found here.
• Note that the log contains data from more than one endpoint connection.  
• All endpoint ID information has been masked.
• Masked data pertinent to this issue has the prefix IPHONE.