How to call a URL from server without showing it to client?

[rlebeau]

You are correct. The error is 'IOHandler value is not valid'

That error means you are requesting an HTTPS url, but the TIdHTTP.IOHandler property has not been assigned a TIdSSLIOHandlerSocketBase-derived component, such as TIdSSLIOHandlerSocketOpenSSL.

Note: if you are using a fairly up-to-date version of Indy from the past few years, TIdHTTP will usually handle that internally for you.

I think ifound the source of the problem. I'm using HTTPS, that requires IOHandles for the SSL/TLS to be assigned

Yes.