LSP :: There are no language servers supporting current mode `so-long-mode' registered with `lsp-mode'.
This issue might be caused by:
1. The language you are trying to use does not have built-in support in `lsp-mode'. You must install the required support manually. Examples of this are `lsp-java' or `lsp-metals'.
2. The language server that you expect to run is not configured to run for major mode
so-long-mode'. You may check that by checking the
:major-modes' that are passed to `lsp-register-client'.
3. `lsp-mode' doesn't have any integration for the language behind `so-long-mode'. Refer to
https://emacs-lsp.github.io/lsp-mode/page/languages and
https://langserver.org/ .
4. You are over `tramp'. In this case follow
https://emacs-lsp.github.io/lsp-mode/page/remote/.
5. You have disabled the `lsp-mode' clients for that file. (Check `lsp-enabled-clients' and `lsp-disabled-clients').
user-error: Minibuffer window is not active