Question Unable to get Plesk to read existing certificates

[PaulM]

Hi,
I've just copied my existing non-Plesk site across to a Plesk 12.x server
Everything is fine except SSL certificates are not working. The certificates I have are Thawte 1-2-3 domain based certificates. The domain has stayed the same but regardless of whether I import the certficates or cut and paste the certificate text I receive "Invalid Certifcate"

I then tried the vhost_ssl.conf entry pointing to the crt. .bundle and .key files. This seems to get ignored as an SSL check shows that the default Plesk certificate is the one being referred.

Is there a specific procedure needed for bringing in existing ( and previously working) certificates?

Regards
Paul