#1 - Do you receive any error messages? I had an "Autoinstaller busy" happen to me when I used Plesk (use Cpanel now) and the fix was:
(Copy/Paste from KB)
Increase timeout values to greater ones (for example 30 minutes) in the Plesk panel server and Plesk panel PHP configuration files:
/usr/local/psa/admin/conf/httpsd.conf:
Timeout 1800
/usr/local/psa/admin/conf/php.ini:
max_execution_time = 1800
We would need to see some logs to assist further.
You should also look at opening a ticket with your Plesk license provider, and they can esclate to Plesk if required.