Please note that you can follow the below procedure to forward the domain domain1.com to domain2.com
1> Login to your plesk control panel.
2> Click on subscriptions.
3> Click on open in control panel.
4> Click on website and domains
5> Click on the domain name at the bottom.
6> Click on change hosting and enter the domain name for which you want to forward.
7> Note that if you forward the domain the contents,malis,database from the domain domain1.com will be removed.
8> Click on ok.
Or you use redirect code like response.redirect in the home page of the domain domain1.com