Unfortunately, there is no other debug information when importing certificates. You can use the keytool command line to see the certificates in the keystore and truststore files. Go to [openfire home]/resources/security and execute the following command lines:
keytool -list -v -keystore keystore
Use this command line to see the certificates imported into Openfire or the self-signed certs created by the server. Pay attention to your certificate and its listed chain.
keytool -list -v -keystore truststore
Use this command line to see the certificates that you server can trust. When you are using a CA that is unknown to Openfire (i.e. Java and XMPP) then you will need to import the root certificate of your Certificate Authority (CA) into this file. You can use the same ketool tool to import root certificates.
FYI, the default password for those files is changeit.