Issue with YAML Language Server integration in Neovim and VSCode

Hello,

I've been facing an issue when trying to use the YAML Language Server (yamlls) with Neovim's built-in LSP client on MacOS 13. While the language server appears to attach correctly to the buffer and my configuration seems to be set up correctly, I'm not getting any syntax highlighting, autocomplete, or suggestions. Additionally, the YAML Language Server is not working in Visual Studio Code either, even when using the official YAML extension.

Here are the relevant details:

• Neovim version: v0.9.1
• Node.js version: v20.2.0
• Visual Studio Code version: 1.78
• YAML Language Server path: /Users/<username>/.local/share/nvim/mason/bin/yaml-language-server --stdio
• I'm using the built-in LSP client with Mason in Neovim, and the official YAML extension in VSCode.
• The YAML Language Server is configured and attached to the buffer correctly according to :LspInfo in Neovim.
• which node returns the expected path to the Node.js binary (/opt/homebrew/bin/node), so Node.js is installed correctly and available in the PATH.
• No errors are appearing in the LSP log (/Users/philipp/.local/state/nvim/lsp.log).
• I've tried restarting my machine, reinstalling Node.js and the YAML Language Server, and manually specifying the path to Node.js in the YAML Language Server configuration in Neovim.

Despite these steps, I'm still not seeing syntax highlighting, autocomplete, or suggestions in YAML files in both Neovim and VSCode. Any guidance on how to debug or fix this issue would be greatly appreciated.

Thank you

No repository files or tests are named. First reproduce the missing YAML highlighting and completion in the reported Neovim and VSCode setups, then inspect the Neovim LSP log and server attachment details. Done means identifying a reproducible cause and restoring language-server features in at least the affected setup.