all the configuration tested are correct but still getting this error:
sourceid.config.ConfigurationException: Unable to lookup sp connection metadata for entityid="SP URL"
Set the FULL URL as captured inside the quotes for "SP URL" as a VSID for the connection. This usually means that Entity ID for the partner has not been set to what they are sending (which is the SP URL).
This can be avoided by making the SP provide you with metadata, and you build the connection around it, then export your own metadata, and send to them. If they can't provide you with metadata, then they should get better at SAML.