v7.56 was the 1st time mIRC switched from using OpenSSL 1.1.0 series to 1.1.1 series, so perhaps that's relevant. If you have an old OpenSSL DLL in the folder you're installing new mIRC into, perhaps there's something in that DLL version which isn't playing nice with the new OpenSSL code. If the next echo shows them pointing to mIRC itself, then that's not the problem.

//echo -a $sslversion $ssldll $ssllibdll

Are you having trouble connecting to other networks via SSL, or just that one?

/server -m chat.freenode.net +6697