[Solved] GSSAPI Error and SSL/TLS negotiation failed

[hundele]

Version of script: hesk345
Hosting company: onprem
Host: Debian 12
URL of phpinfo.php: not visible from outside the LAN

IMAP c-Client Version 2007f
SSL Support enabled
Kerberos Support enabled

URL of session_test.php: -
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Hello we testing hesk, but we have problems fetching the E-Mail vom Exchange 2019 with IMAP.

If I try to use SSL/993 we get the GSSAPI Error:
Unknown GSSAPI failure: No credentials were supplied, or the credentials were unavailable or inaccessible
GSSAPI mechanism status: No Kerberos credentials available (default cache: FILE:/tmp/krb5cc_33)

if I try to use TLS/143 we get the SSL/TLS Error:
TLS/SSL failure for [Server.FQDN]: SSL negotiation failed

Certifiacte are valid
I already activated TLS 1.0/1.1/1.3 and SSL 2/3 on Exchange
PHP Version 8.2 installed
PHP_IMAP are enabled
The connection works with Outlook Client and Thunderbird for this mailbox with IMAP.
The SMTP connection are still working against the Exchange Server via Port 587 in hesk.
And as a secound Test, I was tried to connect to a different E-Mail Server in hesk, which is running under Linux (dovecot), there I get the same Error.s

Is der anything I can check or do in some of the inc/mail Folder config files?

Thanks for any tips.
greetings

[hundele]

Update: I found a solution but it's a little strange.

I just manual edit the config file "hesk_settings.inc.php" with vi in the IMAP Fechting section.

And then I test it with:
/usr/bin/php -q /var/www/html/support/inc/mail/hesk_imap.php

<pre>Connected to the IMAP server &quot;my.server.fqdn:993&quot;.</pre>
<pre>Unread messages found: 1</pre>
<pre>Time limit set to 3600 seconds.</pre>
<pre>Parsing message 1 of 1.</pre>
<pre>Ticket 588-7TD-VB9M created/updated.</pre>
<br /><br />

<pre>Disconnected from the IMAP server.</pre>
<pre>Unknown GSSAPI failure: No credentials were supplied, or the credentials were unavailable or inaccessible</pre>
<pre>GSSAPI mechanism status: No Kerberos credentials available (default cache: FILE:/tmp/krb5cc_0)</pre>

The Error Message are still exist, but the E-Mail got fetched?
I create a cronjob and it's works too.
That's really strange...

Greetings

[Klemen]

Try this (the file is compatible with 3.4.5):
viewtopic.php?t=7161

[hundele]

jep, this works.
Thanks