If you want to test any TLS connection, try openssl:
openssl s_client -connect broker:55443
In the output you can see:
- if port is open
- if tls server certificate is configured
- content of tls server certificate (like: Common Name, issuer,…)
- expiry date of tls server certificate
With the issuer data, you can e.g. configure the validation / certificate authorities on client side.
Obviously, this openssl command is NOT restricted to connect to Solace brokers