I was getting this error too, but I did not know when it started on my mac (maybe a zed update?).

I tried to uninstall zed, compared releases of elixir-ls, etc, but I finally made it work by making the elixir-ls scripts that zed downloads to be executable. Comparing the version between VSCode and zed, I noticed that the elixir-ls release files were not marked as executable:

CleanShot 2024-08-05 at 8 .10.051200×226 38.7 KB

By running chmod +x ... things started to work again.

Just ran across this, might be helpful for someone:
Zed has builtin tailwind support, which can be enabled as well.

Adjust to config as follows:

-     "language_servers": ["elixir-ls"],
+     "language_servers": ["elixir-ls", "tailwindcss-language-server"],

tailwind auto completion in a ~H Heex block for liveview using zed928×374 49.6 KB

The first step should always be looking at the lsp logs, which you can open via the command palette in zed.

Nice, that solved it for me.

Also, I added the following overall config for Elixir, maybe it is useful for someone

Selects the language server and configures format on save.

Most of it was taken from the zed manual

{
  "languages": {
    "Elixir": {
      "show_inline_completions": true,
      "language_servers": ["elixir-ls"],
      "format_on_save": {
        "external": {
          "command": "mix",
          "arguments": ["format", "--stdin-filename", "{buffer_path}", "-"]
        }
      }
    }
  }
}