Crowd authentication between Jira and Confluence breaks when using SSL Certs other than LetsEncrypt

[Arun Ghanta]

We have Jira and Confluence in our infrastructure.

Jira talks to OpenLDAP and syncs the user database.

Confluence authenticates users through Jira's User Server via Jira's Crowd feature.

We have these apps on LetsEncrypt from some time and they work well.

However recently, our company bought Symantec's DigiCerts for these apps.
First two separate SSL certs each for both Jira and Confluence.

After replacing the LetsEncrypt certs with these DigiCert issued SSL Certs, Jira works fine with LDAP and users can login. However Confluence authentication breaks with an error "Sorry cannot log you in".

When looked into logs it shows Java certpath build exception related errors.

Flip both apps back to LetsEncrypt everything works smooth as butter.

We even tried getting a blanket cert containng both these applications SAN names and retry creating JKS.

Still, no go..

Any help is greatly appreciated.