UnityWebRequest shows an "?" when downloading an image from a server

[Kurt-Dekker]

Networking, UnityWebRequest, WWW, Postman, curl, WebAPI, etc:

Using Unity for subscription lists

As with all network code, get it working with Postman or curl first. That makes it NOT a Unity problem. Solve the networking first. You must solve that or anything else is irrelevant. Once you have that working, then try and port it to UnityWebRequest. If it still doesn't work, one handy debug solution is to hook up a proxy like Charles and compare the functioning output from Postman / curl to the output from Unity, and from that reason about where your issues are.

Unity web request acting stupid.

Always get network stuff working outside of Unity in either curl or PostMan, then connect a proxy such as Charles and start trying to replicate the traffic shape with UnityWebRequest. Any other way risks wasting a lot of your time for trivial issues that only the above way will instantly reveal.

And setting up a proxy can be very helpful too, in order to compare traffic:

Using Charles Proxy with Unity

Keep in mind that these images might SEEM to be JPEGs to you but actually be some other wonky newfangled image format that your browser can handle but that Unity cannot handle. Try getting the binary data from the server yourself, including it into the Unity build as a .bytes file and loading it to see if Unity can turn it into a Texture2D or not.

Unity - Manual: Text assets

Unity - Scripting API: TextAsset