As others mentioned, the web version is not working. It happened to me as well, try this:
In unity go to > Build Settings > Player Settings... > Player > and in "Publishing Settings" set "Compression Format" as "Disabled" ? and build your game again.
I also had this problem with my builds, and this setting fixed it (I am running 2020.3.14f1 version of Unity). Feel free to DM me ;)