This started to be an issue since OpenSSL 1.1 is not available anymore on Windows in the Qt installer. The most popular alternative is the build of Shining Lights Productions (https://slproweb.com/products/Win32OpenSSL.html). Library names are different though for their VC versions and although CMake correctly finds these libraries and Poco's CMake build system also set these libraries correctly, the Poco build fails.

This is because of an unfortunate decision of the Poco developers to nevertheless also link verbatim to libcrypto.lib and libssl.lib with #pragma comment(lib) in Crypto.h. Their recommendation to manually edit the file is not a practical advise. We can prevent these pragmas by defining POCO_NO_AUTOMATIC_LIBS, though. The correct libraries are already set by CMake for the Crypto project anyways.

For a fix I will fork Poco and add POCO_NO_AUTOMATIC_LIBS to Crypto.