Null sender got rsp: 550 while earlier build did not.
[2025.12.18] 00:01:14.591 [203.150.x.x][38604880] cmd: MAIL FROM:<> SIZE=2083
[2025.12.18] 00:01:14.591 [203.150.x.x][38604880] senderEmail(1):
[2025.12.18] 00:01:14.591 [203.150.x.x][38604880] rsp: 250 OK <> Sender ok
[2025.12.18] 00:01:14.591 [203.150.x.x][38604880] Sender accepted. Weight: 0. Block threshold: 30.
[2025.12.18] 00:01:14.622 [203.150.x.x][38604880] cmd: RCPT TO:<
abc@domain.com>
[2025.12.18] 00:01:14.837 [203.150.x.x][38604880] rsp: 250 OK <
abc@domain.com> Recipient ok
[2025.12.18] 00:01:14.856 [203.150.x.x][38604880] cmd: DATA
[2025.12.18] 00:01:14.857 [203.150.x.x][38604880] Performing PTR host name lookup for 203.150.x.x
[2025.12.18] 00:01:14.857 [203.150.x.x][38604880] PTR host name for 203.150.x.x resolved as mail.domain.com
[2025.12.18] 00:01:14.858 [203.150.x.x][38604880] rsp: 354 Start mail input; end with <CRLF>.<CRLF>
[2025.12.18] 00:01:14.889 [203.150.x.x][38604880] Tried parsing FROM, detected null/empty/bad result, defaulting back to . Line: From: "System Administrator"
[2025.12.18] 00:01:14.889 [203.150.x.x][38604880] rsp: 550 From address must match authenticated address | Info: Message missing mail from and not multipart/report
[2025.12.18] 00:01:14.903 [203.150.x.x][38604880] Successfully wrote to the HDR file. (C:/SmarterMail/Spool/SubSpool1/26522860530.hdr)
[2025.12.18] 00:01:14.903 [203.150.x.x][38604880] data transfer failed.
[2025.12.18] 00:01:14.903 [203.150.x.x][38604880] disconnected at 12/18/2025 12:01:14 AM
Below is from 9245
[2025.12.18] 13:38:18.819 [203.150.x.x][28512142] rsp: 250 OK <> Sender ok
[2025.12.18] 13:38:18.819 [203.150.x.x][28512142] Sender accepted. Weight: 0. Block threshold: 30.
[2025.12.18] 13:38:18.849 [203.150.x.x][28512142] cmd: RCPT TO:<
abc@domain.com>
[2025.12.18] 13:38:20.115 [203.150.x.x][28512142] rsp: 250 OK <
abc@domain.com> Recipient ok
[2025.12.18] 13:38:20.129 [203.150.x.x][28512142] cmd: DATA
[2025.12.18] 13:38:20.129 [203.150.x.x][28512142] Performing PTR host name lookup for 203.150.x.x
[2025.12.18] 13:38:20.129 [203.150.x.x][28512142] PTR host name for 203.150.x.x resolved as mail.domain.com
[2025.12.18] 13:38:20.132 [203.150.x.x][28512142] rsp: 354 Start mail input; end with <CRLF>.<CRLF>
[2025.12.18] 13:38:20.166 [203.150.x.x][28512142] Tried parsing FROM, detected null/empty/bad result, defaulting back to . Line: From: "System Administrator"
[2025.12.18] 13:38:20.194 [203.150.x.x][28512142] DMARC Results: Skipped (Authenticated), Reason: Unknown, Reject? False
[2025.12.18] 13:38:20.194 [203.150.x.x][28512142] rsp: 250 OK
[2025.12.18] 13:38:20.199 [203.150.x.x][28512142] Received message size: 2394 bytes
[2025.12.18] 13:38:20.201 [203.150.x.x][28512142] Successfully wrote to the HDR file. (C:/SmarterMail/Spool/SubSpool0/12318180656.hdr)
[2025.12.18] 13:38:20.225 [203.150.x.x][28512142] cmd: QUIT