Not able to install mailspring on one of my computers

Service Issues
1

Subject: SMTP Authentication Error (Code 296) on Windows - Hostinger Mail

Problem Description:
I am unable to set up my Hostinger email account in Mailspring on one specific Windows machine, while the same settings work perfectly on two other computers. Other email clients (Outlook and Opera Mail) work without issues on this same PC.

Technical Details:

  • OS: Windows (Desktop-FUSPE94)

  • Mailspring Version: (Upišite verziju koju koristite, npr. 1.13.3)

  • OpenSSL Version (from log): OpenSSL 3.6.0 1 Oct 2025

  • Server: smtp.hostinger.com (Port 465 SSL/TLS and Port 587 STARTTLS tested)

  • Error Code: mailsmtp Last Error Code: 296 (Unknown)

  • Error Location: 10

  • Auth Type: 2

Observed Behavior:
The IMAP connection and login are successful. However, the SMTP connection fails immediately after the STARTTLS or during the AUTH phase.

  • Firewall and Antivirus were disabled during testing – no change.

  • “Allow insecure SSL” was checked – no change.

  • Tested with both hostname and IP address – when using IP, a certificate has expired error appears in OpenSSL log, even though the system clock is synchronized.

  • The log shows 220 2.0.0 Ready to start TLS, but fails at mailsmtp Last Error Location: 10.

Attached Logs:

----------IMAP----------
connect mailcore::IMAPSession:00EFF788

  • OK [CAPABILITY IMAP4rev1 SASL-IR LOGIN-REFERRALS ID ENABLE IDLE LITERAL+ AUTH=PLAIN AUTH=LOGIN] Server ready.
    TLS ssl connect imap.hostinger.com 993 2
    OpenSSL version: OpenSSL 3.6.0 1 Oct 2025
    connect ok
    login
    1 LOGIN “info@krizanic-print.hr” “*********”
    1 OK [CAPABILITY IMAP4rev1 SASL-IR LOGIN-REFERRALS ID ENABLE IDLE SORT SORT=DISPLAY THREAD=REFERENCES THREAD=REFS THREAD=ORDEREDSUBJECT MULTIAPPEND URL-PARTIAL CATENATE UNSELECT CHILDREN NAMESPACE UIDPLUS LIST-EXTENDED I18NLEVEL=1 CONDSTORE QRESYNC ESEARCH ESORT SEARCHRES WITHIN CONTEXT=SEARCH LIST-STATUS BINARY MOVE SNIPPET=FUZZY PREVIEW=FUZZY PREVIEW STATUS=SIZE SAVEDATE LITERAL+ NOTIFY SPECIAL-USE COMPRESS=DEFLATE QUOTA] Logged in
    2 COMPRESS DEFLATE
    2 OK Begin compression (0.001 + 0.000 secs).
    3 ENABLE QRESYNC
  • ENABLED QRESYNC
    3 OK Enabled (0.001 + 0.000 secs).
    4 NAMESPACE
  • NAMESPACE ((“INBOX.” “.”)) NIL NIL
    4 OK Namespace completed (0.001 + 0.000 secs).
    login ok
    5 LIST “INBOX.” “*”
  • LIST (\HasChildren \UnMarked) “.” INBOX.Mailspring
  • LIST (\HasNoChildren \UnMarked) “.” INBOX.Mailspring.Snoozed
  • LIST (\HasNoChildren \UnMarked) “.” INBOX.axxxxxGOTOVOxxxxxx
  • LIST (\HasNoChildren \UnMarked) “.” INBOX.LEA
  • LIST (\HasNoChildren \UnMarked) “.” INBOX.MARIJA
  • LIST (\HasNoChildren \UnMarked) “.” INBOX.cijene
  • LIST (\HasNoChildren \UnMarked) “.” “INBOX.marija prijelazno”
  • LIST (\HasChildren \UnMarked) “.” “INBOX.KRE&AWA-O RADI”
  • LIST (\HasNoChildren \UnMarked) “.” “INBOX.KRE&AWA-O RADI.kre&AWE-o VA&AX0-NO”
  • LIST (\HasNoChildren \UnMarked) “.” “INBOX.KRE&AWA-O RADI.kre&AWE-o prijelazno”
  • LIST (\HasNoChildren \UnMarked) “.” “INBOX.ZA NAPRAVITI PONUDU”
  • LIST (\HasNoChildren \UnMarked) “.” “INBOX.ZA NAPISATI RA&AQw-UN”
  • LIST (\HasNoChildren \UnMarked \Trash) “.” INBOX.Trash
  • LIST (\HasNoChildren \UnMarked \Sent) “.” INBOX.Sent
  • LIST (\HasNoChildren \UnMarked \Junk) “.” INBOX.Junk
  • LIST (\HasNoChildren \UnMarked \Drafts) “.” INBOX.Drafts
    5 OK List completed (0.001 + 0.000 secs).
    6 LIST “” “INBOX”
  • LIST (\HasChildren) “.” INBOX
    6 OK List completed (0.001 + 0.000 secs).

----------SMTP----------
connect smtp.hostinger.com 587
220 ESMTP smtp.hostinger.com
init
EHLO DESKTOP-FUSPE94

250-smtp.hostinger.com

250-PIPELINING
250-SIZE 48811212
250-ETRN
250-STARTTLS
250-AUTH PLAIN LOGIN
250-ENHANCEDSTATUSCODES
250-8BITMIME
250-DSN
250 CHUNKING
start TLS
STARTTLS
220 2.0.0 Ready to start TLS
done
init after starttls
EHLO DESKTOP-FUSPE94

250-smtp.hostinger.com

250-PIPELINING
250-SIZE 48811212
250-ETRN
250-AUTH PLAIN LOGIN
250-ENHANCEDSTATUSCODES
250-8BITMIME
250-DSN
250 CHUNKING

SASL_PATH:

SMTP Last Response Code: 250
SMTP Last Response: smtp.hostinger.com
PIPELINING
SIZE 48811212
ETRN
AUTH PLAIN LOGIN
ENHANCEDSTATUSCODES
8BITMIME
DSN
CHUNKING

mailsmtp Last Error Code: 296
mailsmtp Last Error Explanation: Unknown
mailsmtp Last Error Location: 10
mailsmtp Last Auth Type: 2

2

Issue resolved by downgrading to version 16