delete everything from this file: /usr/local/apache/conf.d/vhosts-ssl.conf
/etc/pki/tls/certs
delete your domain certificates files from here .crt,.cert,.bundle
/etc/pki/tls/private
delete your domain key file
Goto ssl generator fillin the entries and at the bottom also tick generate self signed certificate. Now generate ssl
Now this will generate csr, crt and key file.
Now you can goto ssl cert manager and complete rest of the process.