Yes. one can remove domain restrictions. In order to remove the added domains, you can.
1.Click on the “Settings” option in the side-navigation bar.
2. Select “General” in the drop-down.
3. Once done, click on the “User” tab as shown in the screenshot.
4. Here, click on the “+Domain Restriction” option in “Social Settings” as shown in the screenshot below.
5. Remove the domains here and “Save” once done.