I don't understand your question. Games uploaded to Itch should not have an installer. Just put it in a zip archive. But Itch isn't going to stop you from uploading an installer if you make one. How big is your game? There's a size limit. And why can't you contact support?
When I archive my project it's just 10 M.B. So there is no problem with the size. But when I upload this it saws, "There was a problem completing your upload. Try again. If the problem persists contact support." Clicking on contact support, it take me to a place where the first contact support is on twitter. I have an twitter account and it saws can't message itch.io. Because that is a page. And there are no other contact support options. I don't know is the file is not supported or there are any other problems.
It's @itchio, without a dot, and right below that on the support page there's a big red button that says E-mail support@itch.io. If neither works, I can let an admin know. Maybe your internet connection is slow, but it's best to check. Hope this helps!
Now I think it's because of slow internet connection. I even don't know how to check internet speed but when I download something I see the speed is under 10 K.B.(Minimam) to 150K.B.(Maximum). The E-mail support@itch.io takes me to a blank page which never respond. I have tryed uploading another file which I have uploaded before. That is not also uploading. So I don't think that the files have no problem. The problem now would be on my acoount, itch.io or can be my internet connection. Whatever , now I'll try to solve the problem myself. But If anyone knows how to solve the problem please help me by replying!
Not that one, when your run paused for this error there must be a new window where details of object of error would seen. I want you to saw the object. If you haven't understood what window I'm talking about just run and take a screenshot of godot when it paused for the error.(But don't take screenshot of your game which is running)
Bro, I'm happy that I've now suddenly abled to upload the game flappy bird! You can try playing this game here - "https://uotsab-chakma.itch.io/flappy-bird"