The anope-openssl package in EL7 seems to be built against the system libssl, but linked against openssl 1.1.1, which lacks some symbols, making the m_ssl_openssl.so module not load (and an ssl connection to the irc server fails, tested with inspircd20):

In the anope logs:

/usr/lib64/anope/modules/m_ssl_openssl.so: undefined symbol: SSLv23_client_method

$ nm -D /usr/lib64/anope/modules/m_ssl_openssl.so| grep SSLv23
U SSLv23_client_method
U SSLv23_server_method
$ nm -D /usr/lib64/libssl.so.1.1.1c | grep --count SSLv23 # The current stable version of openssl11-libs 
0
$ nm -D /usr/lib64/libssl.so.1.0.2k | grep SSLv23 
000000000002f660 T SSLv23_client_method
000000000002eb10 T SSLv23_method
000000000002eb70 T SSLv23_server_method