Forwarded to devs change from medium/relaxed TLS Versions to modern breaks Plesk-Webmail

[Nextgen-Networks]

Username: Nextgen-Networks

TITLE

change from medium/relaxed TLS Versions to modern breaks Plesk-Webmail

PRODUCT, VERSION, OPERATING SYSTEM, ARCHITECTURE

Plesk 18.0.37 MU2 + SSLit 1.9.3-1288
Ubuntu 20.04.3
x64

PROBLEM DESCRIPTION

After facing massive SSL problems with postfix/dovecot with able to send E-Mails via SMTP I've changed the used Cipher Suites from medium/relaxed to modern within SSLit! extension provided by Plesk.
This "modern" setting breaks the build-in Webmail Service of Plesk

STEPS TO REPRODUCE

Change SSLit CiperSuites/TLS settings from medium to modern


ACTUAL RESULT

Webmail is not reachable anymore - you'll face this HTTP error:

502 Bad Gateway​

---

nginx

EXPECTED RESULT

Webmail should work as before and as on a other server I manage with Plesk 18.0.37 MU2 and Ubuntu 18.04 LTS

ANY ADDITIONAL INFORMATION



YOUR EXPECTATIONS FROM PLESK SERVICE TEAM

Confirm bug

 

[IgorG]

Thank you. Confirmed and submitted as PPPM-13038

Workaround: Rollback to TLS 1.2 using the following command:

# plesk sbin sslmng -s apache --protocols=TLSv1.2 --ciphers=`openssl ciphers -s -tls1_2`

 

[IgorG]

Fixed in Plesk Obsidian 18.0.38