Jenkins + Konakart Mail issue

Hi,

i have a strange issue on my Payara since some Versions.

If Konakart is sending a Mail, i get this error:

21-Apr. 19:54:04 WARN (EmailSender.java:run:52) Problem Sending email (subject: Email From Tachyon Online) to info@example.de
com.konakart.app.KKException: Error sending email: class io.jenkins.plugins.javax.activation.DelegatingCommandMap cannot be cast to class java
x.activation.MailcapCommandMap (io.jenkins.plugins.javax.activation.DelegatingCommandMap is in unnamed module of loader jenkins.util.AntClassL
oader @19a266b2; javax.activation.MailcapCommandMap is in unnamed module of loader org.apache.felix.framework.BundleWiringImpl$BundleClassLoad
er @768b6f47)
at com.konakart.bl.Emailer.send(Emailer.java:998)
at com.konakart.bl.EmailSender.run(EmailSender.java:49)
at java.base/java.lang.Thread.run(Thread.java:829)

]]

When i disable Jenkins, the mail is sent.

Any hints?

Thx
Andreas

Linux openSUSE Leap 15.3
openjdk version “11.0.14.1” 2022-02-08
Konakart Version 9.4.0.2
Jenkins Version 2.344