We have a on premise Suse/Tomcat/Jira installation.
From architecture perspective we have to go through proxy to Internet. So we set Proxy settings and account credentials inside the tomcat setenv.sh.
Which is fully working as we can see the Attlassian marketplace. So the internet connection itself is working.
Now we want to set up incoming mail with O365 (https://outlook.office.com) My Architekture Proxy team have setup a TCP tunnel to O365.
By testing the connection we get the error message: "SunCertPathBuilderException: unable to find valid certification path to requested target"
We followed the instructions in https://confluence.atlassian.com/jira/connecting-to-ssl-services-117455.html?_ga=2.64731180.2099425676.1508846557-1422747846.1508846557 (installing public cert from https://outlook.office.com in java keystore) but without any success.
Anybody has an idea how to proceed?
Additional Info:
Installed Jira on a private machine and using the same Microsoft O365 credentials and it's working without any certifacte issue...