Are there any other details whatsoever? Like, do they get to the Wikimedia screen? Are they redirected back? Can we get a screenshot of where they get stuck?

@Richard_Nevell_WMUK may be able to get some information from the juror who experienced this problem, but before then, maybe we can ask @Effeietsanders to test this. Lodewijk, can you check if you run into an issue if you try to log in while on IE?

I was surprised to find that MIE is still on my computer after I moved to Edge! Wow, another gem in life uncovered ;). But it's an app, not sure if it's the same.

I can however confirm the bug:

• I go to https://tools.wmflabs.org/montage-beta/#/login
• I click on 'sign in using Wikimedia account'
• I'm sent to metawiki to log in
• after completing login on metawiki, I'm sent back to the identical login screen on https://tools.wmflabs.org/montage-beta/#/login
• after clicking the sign in button again, it just refreshes the page (after showing a waiting symbol for a second or two) and shows me the login screen again on https://tools.wmflabs.org/montage-beta/#/login - not taking me to meta again.

In the MIE console I see the following warnings:

• DOM7011: The code on this page disabled back and forward caching. For more information, see: http://go.microsoft.com/fwlink/?LinkID=291337 montage-beta
• HTML1500: Tag cannot be self-closing. Use an explicit closing tag. montage-beta (8,3)
• DOM7011: The code on this page disabled back and forward caching. For more information, see: http://go.microsoft.com/fwlink/?LinkID=291337 montage-beta
• HTML1521: Unexpected "</body>" or end of file. All open elements should be closed before the end of the document. montage-beta (16,77)

In T149472#2753753, @Effeietsanders wrote:

I was surprised to find that MIE is still on my computer after I moved to Edge! Wow, another gem in life uncovered ;). But it's an app, not sure if it's the same.

I can however confirm the bug:

• I go to https://tools.wmflabs.org/montage-beta/#/login
• I click on 'sign in using Wikimedia account'
• I'm sent to metawiki to log in
• after completing login on metawiki, I'm sent back to the identical login screen on https://tools.wmflabs.org/montage-beta/#/login
• after clicking the sign in button again, it just refreshes the page (after showing a waiting symbol for a second or two) and shows me the login screen again on https://tools.wmflabs.org/montage-beta/#/login - not taking me to meta again.

In the MIE console I see the following warnings:

• DOM7011: The code on this page disabled back and forward caching. For more information, see: http://go.microsoft.com/fwlink/?LinkID=291337 montage-beta
• HTML1500: Tag cannot be self-closing. Use an explicit closing tag. montage-beta (8,3)
• DOM7011: The code on this page disabled back and forward caching. For more information, see: http://go.microsoft.com/fwlink/?LinkID=291337 montage-beta
• HTML1521: Unexpected "</body>" or end of file. All open elements should be closed before the end of the document. montage-beta (16,77)

That is exactly what happened for the juror (I was in the same room so able to see for myself). I didn't check the console at the time. MIE was being used on a Windows 10 computer, so I presume it was an app.

HTML1500: Tag cannot be self-closing. Use an explicit closing tag. montage-beta (8,3)

See the source code of https://tools.wmflabs.org/montage-beta/#/login :

<ui-view/>

@Yarl you looked into this task a few days ago. Can you document here what the problem is and let us know how we should proceed?

I understand that for the current round, you said that we should discourage the use of IE. Is this something that we should always be doing, i.e., we signal that Montage doesn't support IE?

I'm going to decline this task given that it's been around for a long time. re-open if it's unresolved.