Public Preview: High Volume Email for Microsoft 365

All our printers have been configured to email with an HVE account for several months now.  The past few weeks some printers sometimes fail STARTTLS, from what we can tell (we are still investigating).  All printers support and use TLS 1.2.  It seems the failure is the cipher suite negotiation - we think printers not supporting elliptical curve ciphers.  The failures are not 100% of the time, so we are still diagnosing.    The printers are for the most part using their latest firmware.  We do have an example of one printer that would sporadically fail, even though it supported TLS 1.2.  It was not at the latest firmware and an upgrade seems to have solved that printer's issue.  Is the HVE endpoint not offering all TLS 1.2 cipher suites?  Can you provide a list of ciphers supported by the HVE endpoint?  Thank you.