Error after updating the composer

I have never try to upgrade any project from laravel 11 to 12 ... so I am working on the project and I thought to upgrade this project

my current project was like this

  Application Name ........................ Laravel  
  Laravel Version ...................... 11.44.1  
  PHP Version ...................... 8.2.28  
  Composer Version ....................... 2.7.2
  Environment ............................ local  
  Debug Mode .................. ENABLED  
  URL ............................... localhost:8000  
  Maintenance Mode..................... OFF  
  Timezone................................. Asia/Kolkata  
  Locale............................. en  

after that I copy this project just incase as backup and i run the composer update command i self-update the composer to version 2.8.9 there was some error while upgrading the project so i decide not to upgrade now i am back to old project but my composer.json file is thawing the following warning

Problems loading reference 'https://getcomposer.org/schema.json': Unable to load schema from 'https://getcomposer.org/schema.json': .

i don't know what should i do ?? please helpppppp