DominoPDF uses 2 DLL’s to connect via HTTPS / SSL which are named ssleay32.dll and libeay32.dll.
Notes / Domino v8 and later has another version of the SSL DLL (libeay32.dll) in Domino directory; \domino_icc\icc\osslib
This Notes / Domino directory handles the new FIPS 140-2 certified cryptography library for Notes / Domino v8, so if you’re looking to deploying FIPS 140-2 certified Notes ID and document encryption there may be a conflict with DominoPDF.
To work around this issue, DominoPDF exposes a setting UseIEHTTP=True, which uses an alternate SSL library.