uses IdOpenSSL, // ... other units ...
Before diving into solutions, it is critical to understand this error happens. Indy does not natively speak SSL/TLS. Instead, it acts as a wrapper around two external dynamic link libraries (DLLs) from the OpenSSL project: Delphi 7 Indy 9 Could Not Load Ssl Library
Do not download standard OpenSSL files from modern distributions. You need the archived, customized files specifically compiled for Indy 9. Delphi 7 Indy 9 Could Not Load Ssl Library - Google Groups uses IdOpenSSL, //
Recommended OpenSSL builds for Indy 9 + Delphi 7 Delphi 7 Indy 9 Could Not Load Ssl Library