This is happening on DHL eCommerce.
The initial refresh worked, but no new refresh have worked since Jan 8th. The pop-up browser window shows this error message:
You don't have permission to access "http://www.dhl.com/global-en/home/tracking.html?"
on this server.
When it did sync, the pop-up showed a 3 sec countdown which you can reproduce by opening the link in an Incognito tab.
Hence, it seems likely the issue might be cookie related.
Maybe it's still using the cookie from that first sync, but it's no longer valid on their end.
I don't think there is a way to manually clear the apps stored cookies?
"Show in browser" works fine, whether using the built-in browser or an external one.