Hi Omolara,
I have seen this happen when Pro cannot access the license manager involved in handing out the Pro licensing.
If you know the hostname/IP address of the machine where the license manager is installed on, as well as the port number used by the license manager (the default is 27000), you can do the following test:
Open a browser on your computer and enter http://machinename:port or http://ipaddress:port
Example:
http://license.esri.com:27001
If it displays "Wê-60Wê-60Wê-60Wê-60Wê-60Wê-60" in the browser (in Chrome it will download a file with this string), then your machine does have access and you are probably facing another issue.
If not, verify the following:
1) The license manager is started
2) The firewall is open for the port being used by the license manager
3) In the License Server Administrator program, go to "Availability" and make sure there are licenses available for the "Named User" line.
I hope this helps!
-Danny