Please follow this procedure for unblocking a user:
1. First, you need to click on the top right-hand corner of the page and select ‘Display name/User name’
2. Then, go to settings.
3. Now select the Blocked Users option
4. Select the blocked user to do Unblock.
5. Click on the top right side three-dot button next to the profile icon.
6. Now, select the Unblock option.