Problem installing the certificate

How to enter the certificate I bought in openfire. The seller provided me with four files named AAA_Certificate_Services.crt, Sectigo_RSA_Domain_Validation_Secure_Server_CA.crt, mysitename_com.crt, USERTrust_RSA_Certification_Authority.crt, mysitename.com.key. Please guide how, I can use them.
Currently, I went to Server ====> TLS Certificates ===> Identity store ===> Manage Store Contents and in the private key field I entered the contents of the mysitename.com.key file and in the certificate field the contents of the mysitename_com file. I entered the crt, but after confirming and restarting the openfire service, the message A certificate for the domain of this server is missing. Click here to generate a self-signed certificate or here to import a signed certificate and its private key. gives If it accepts the certificate I entered

Openfire will check for various domain names to be present in the certificate, including the XMPP domain name but also subdomains, like the conference domain and the pubsub domain. It appears that some of these are missing in your certificate.

This typically is a problem only when users on other domains want to access those services directly (eg when a user of another domain wants to join a chatroom on your service).

Thank you for your response. This message is being displayed on the Openfire server, and users from other domains do not want to connect to my Openfire domain.