Outlook webpage not working properly

[tortoisedoc]

Opening mailbox takes forever;
selecting a mail first results in the browser asking if it should open it in another tab.
In order to open it, it takes a weird "fast" click of sorts.

Also, the "open in a new tab" does not seem to work (as doesnt the setting to remember the selection).
However, keeping a link pressed, and opening it from the "native" "open in a new tab" works.

[tortoisedoc]

One quick note:
if I leave the pages to load properly, it appears eventually the browser won't crash.

Meaning:
I usually open the mail box, then switch to the "Focussed" tab.
On ESR91 it takes a loooong time to display the list of mails there.
If, once the list has appeared, I select a mail right away, the browser attempts to open it, but crashes right after it.

However, if I wait say a few minutes, the mail opens (loaded) and the browser doesnt crash.

Thread issue?