If you cannot share your website link on Facebook, it could mean that your domain is blocked by Facebook. This can happen for several reasons but most of the time, it is blocked due to spamming with the link on Facebook. It means that the link (or the domain) has been shared on Facebook in an unusual manner. Facebook does not tolerate any type of spamming. If this happens for your website, you can check the reason for your ULR block from here: https://developers.facebook.com/tools/debug/ and take actions according to it.
There is nothing that can be done as a hosting provider to unblock your domain from Facebook as we do not control it. You need to do this by yourself or take help from your website developer.
If you can not remove the URL block for your domain for some reason, changing the website URL can be another option. For this, you need to buy a new domain and contact us via support, and we will help you change the domain in cPanel.