Whenever i try to remove background from the video it dosen't load it, takes lots of time and app hangs and closes as soon as i try again.

I don’t have an immediate solution right now, but I still wanted to share some stuff that works for me.
First of all, on desktop:
The immediate thing to test out is to clear the cache of your browser, or if you don’t want to do that right now, test it on a new browser, you will have to sign in again, but apart from that you can just copy and paste the URL in another browser and you’ll get the same page.
Accepted browsers are Edge, Chrome, Safari and Firefox, Firefox can be temperamental (again, my experience) so double check with any other one as well.

That goes if you also work from the Progressive Web App.
Cache can get very bloated with video and that’s something you will need to pay attention to at some point. It’s good practice to clear it from time to time anyway.
Second step, if the first one didn’t solve the issue is to log out and log in again: It can solve problems liked to your account.
Third step: Check if there’s some maintenance going on where you are, you can check here → https://status.adobe.com/

It will tell you what’s happening and you can also subscribe to receive notifications when it happens.
Know that even if the app is on hold, your files are safe and sound tucked on the cloud.
You can check them here: → https://www.adobe.com/files

On mobile, log out and then in again, and if all fails, delete the app, and download it again. (again, your files are safe, they are tied to your account)

If it doesn’t work, please answer with
The device/s you’re using and the steps you have already taken from the list above.