Yesterday I installed WAS 8.5.5 FP28 on a customer environment with 2 interim fixes ( IFPH68976 and IFPH69757 ) because of some security issues.

Today I received the information that the PDF export for Wikis is no longer working.

Looking in the SystemOut.log I could see a lot of the following errors:

java.security.cert.CertificateException: No subject alternative DNS name matching hostname found

There´s an article in the HCL knowledge base which is offering one solution to add the servers in the hosts but you also can solve this issue by adding the following entry in the custom properties of the server hosting the PDF export:

com.ibm.ssl.verifyHostname = false

After adding this value and restarting the server the PDF export was working again.