Analysis of the test results of mail messages from the port25.com service - what is what?

Question

Software testing

Once upon a time, someone advised the https://www.port25.com/support/authentication-cent... service to test the mail server from which the distribution is planned.
We decided to try: we sent a test email to: [email protected] and received a response:
============================ ==============================

Summary of Results
============================================== ===========
SPF check: pass
DomainKeys check: neutral
DKIM check: pass
Sender-ID check: pass
SpamAssassin check: ham

Where pass is, of course, the test is passed, but opposite SpamAssassin check is the value
ham, the decryption says:

-------------------------------------------------- --------
SpamAssassin check details:
-------------------------------------- --------------------
SpamAssassin v3.4.0 (2014-02-07)
Result: ham (-3.0 points, 5.0 required)
pts rule name description
---- ------------------------------------------------ ----------------------
-0.0 SPF_HELO_PASS SPF: HELO matches SPF record
-0.0 SPF_PASS SPF: sender matches SPF record
-1.0 RP_MATCHES_RCVD Envelope sender domain matches handover relay domain
-1.9 BAYES_00 BODY: Bayes spam probability is 0 to 1%
[score: 0.0000]
0.0 HTML_MESSAGE BODY: HTML included in message -0.1
DKIM_VALID_AU Message has a valid DKIM or DK signature from author 's
domain

What does it all mean? What's wrong with us? What requires additional configuration on the mail server or domain, or is everything fine?