My image upload didn't work, see here: https://imgur.com/a/5L0Y1we

It is usually ok to post image on comment after creating the question. If it fails - it's usually due to a bad gateway issue - refresh the page and then try again.

Have you set up to allow cookies in Thunderbird? If no then make sure it is set up.

• Select 'Menu app icon' > 'Preferences' > 'Privacy & Security '

Under 'Web Content'

• Select 'Accept cookies from sites'

You mention 'bugs' in the view

Is that the first view you see when it opens? Is that what you see after entering password and clicking on Sign In ? Image below.

Yes, we are accepting all cookies.

Other than the black boxes added to obscure identifiable information this is exactly what we get. Missing text/labels, no buttons to proceed. We then tried OWL plugin to set up as an Exchange account and the authentication for that also opens in a similar window with missing labels and controls on the form.

This is running on latest automatic update of Thunderbird as of today.

Had the same problem, found a solution [https://support.mozilla.org/en-US/que.../1392072] by user "Tussilago". Here is what solved it for me: "It was enough to remove "general.useragent.override" entry in the Config Editor in Settings and restart Thunderbird."