Don't have IE on my S9 Samsung have Chrome.. What I do know is when I tried to access the WebUI over Chome on my S9 it tells me I need the Plugin for cameras that still require it.. However something that is cool for me if I am in a bind and want to make a camera change that I can't do over the App.. I can log in on Chrome goto setup and make changes inside there even without the plugin
However crazy as it is LOL my camera that is on a Chrome Updated FW from 2019 and 2020 I can use Chrome to log in over my S9 and it does look like it should besides it is super sized lol Making it smaller does let me access all the functions of the camera.. I just had to check after your Question if it would work on the new FW from 2019 and 2020 and it did..
However I am going to guess that is your system isn't letting you use the app very well Chrome or IE if you were able to install plugin might not work so well either Just a Guess...