Postfix SMTP server: errors from saiph.bhusd.org[

Me being new to Postfix/Dovecot can someone tell me what this means?!??!?!

Transcript of session follows.

Out: 220 ns1.android-x86.net ESMTP Postfix
In: EHLO saiph.bhusd.k12.ca.us
Out: 250-ns1.android-x86.net
Out: 250-PIPELINING
Out: 250-SIZE
Out: 250-VRFY
Out: 250-ETRN
Out: 250-STARTTLS
Out: 250-AUTH -------------
Out: 250-AUTH=--------------
Out: 250-ENHANCEDSTATUSCODES
Out: 250-8BITMIME
Out: 250 DSN
In: MAIL FROM:SpamServer@bhusd.org SIZE=502
Out: 250 2.1.0 Ok
In: RCPT TO:Myers.154@android-x86.net
Out: 550 5.1.1 Myers.154@android-x86.net: Recipient address rejected: User
unknown in virtual alias table
In: RSET
Out: 250 2.0.0 Ok
In: MAIL FROM:<> SIZE=2242
Out: 250 2.1.0 Ok
In: RCPT TO:Myers.154@android-x86.net
Out: 550 5.1.1 Myers.154@android-x86.net: Recipient address rejected: User
unknown in virtual alias table
In: QUIT
Out: 221 2.0.0 Bye

Why/How are the E-Mail Address with MY Forum Extension: “Myers.154@android-x86.net

I did a Mass E-mail Yesterday to inform members that’ll I’ll be moving to the new forum, And I got 4 of these,

Can anyone let me know exactly what this is, I see that it’s not going anywhere, as they aren’t in the Alias log, OH, Is it that someone just treid to use that to send an E-mail?
I searched the forum members E-mails and none of the have my extension…

Thanks for any insight on this.

Mike