You might notice that at some point, your icons do not look fine, and look like squares (see bellow)
This issue is caused by CORS (Cross-Origin Resource Sharing). You can find more about this here
CORS is a mechanism that allows restricted resources (e.g. fonts) on a web page to be requested from another domain outside the domain from which the first resource was served.
In your case, this might be caused by changing the domain, or by your host.
In order to fix this, please check the solutions bellow.
1) Please make sure that you entered the new/updated URL
2) Another solution, is to modify the .htaccess file (which you should find in your root folder). Please make a backup of this file, before making any changes.
At the end of .htaccess file please add this lines and check your icons.
Header set Access-Control-Allow-Origin “*”