WHM hanging when requesting mutable data authorisation

[calumcraig]

Pre requisites:
SAFE browser is open, user is logged in. WHM app has been authorised from browser.

Steps to reproduce:

• create a new public ID
• create a website for this ID
• remap the location of the website
• click (new) location to attempt to get container info
• get a "Mutable Data Authorisation" pop up dialog - click OK

Expected:
WHM app receives authorisation and user is able to proceed.

Actual:
WHM app hangs and only way to proceed is to close it:

Environments:
Found on Linux Mint 19 Cinnamon.
Replicated in Windows 10 VM.