So, check your certificate license.
If it's allowed the install on more than one server, there are two methods to do it:
The first method is to import the certificate, private key, and intermediate files on server #2, #3, etc.
The first method is to import the certificate, private key, and intermediate files on server #2, #3, etc.
The second one: create a new CSR and key file on server #2, #3, etc. and reissue the active certificate.