Due to DNS changes, users using certain browsers with DNS caching features could not load the application anymore. This issue affected existing Zephyr Scale users who were using Firefox with DNS caching enabled.
Firefox was the only browser identified to present this issue and its standard configuration for invalidating the DNS cache is one hour. After the Firefox cache has been invalidated, Zephyr Scale was again accessible to all users.
The issue started around 1:30 pm BST and we got confirmation that it had been fixed about an hour later.