IntelliSense not working

Hello there and good day all.
I love vscode and its really awesome. thanks for creating this editor. it made my life easier.
first when i installed vscode the IntelliSense was not detecting a lot of the problems until i compiled my code.
but recently it has stopped working all together. even after i compile my code the errors are not detected anymore.
i have to read my console and manually find the error.
since gcc 's errors are really hard to read since gcc writes all the namespace names and aliases.
it has been making my coding as hard as it was before i found vscode.
i have searched for this issue and tried everything but i cant seem to get it to work.

im using:
ubuntu 20.04 LTS
vscode version 1.65.0
c++ extension v1.8.4

all my active extensions are:
Auto hide
Bracket Pair Colorizer 2
C/C++
C/C++ extension pack
Docker
Doxygen Documentation Generator
Makefile Tools
Python
Remote - Containers
Remove - SSH

this is my setting.json
{
"[dart]": {
"editor.formatOnSave": true,
"editor.formatOnType": true,
"editor.rulers": [
80
],
"editor.selectionHighlight": false,
"editor.suggest.snippetsPreventQuickSuggestions": false,
"editor.suggestSelection": "first",
"editor.tabCompletion": "onlySnippets",
"editor.wordBasedSuggestions": false
},
"workbench.iconTheme": "vscode-icons",
"files.autoSave": "afterDelay",
"editor.fontFamily": "Fira Code",
"editor.fontLigatures": true,
"editor.fontSize": 15,
"git.autofetch": true,
"window.zoomLevel": 1,
"terminal.integrated.tabs.enabled": false,
"editor.cursorSmoothCaretAnimation": true,
"bracket-pair-colorizer-2.depreciation-notice": false,
"files.exclude": {
"/.classpath": true,
"/.project": true,
"/.settings": true,
"/.factorypath": true
}
}

thank you very much