Class 'DI\ContainerBuilder' not found

how to solustion in phpmaker 2021?
Fatal error: Uncaught Error: Class ‘DI\ContainerBuilder’ not found in C:\xampp\htdocs.….…\index.php:35 Stack trace: #0 {main} thrown in C:\xampp\htdocs.….…\index.php on line 35

Make sure you have run composer update. If you do not know what is "composer update’, read: https://phpmaker.dev/doc/sysreq.htm#composer.

You better

  1. Click Tools → Delete Template Cache,
  2. Delete all files in your project file and generate all files again,
  3. Make sure composer update is run successfully after generation.

error still appears
Fatal error: Uncaught Error: Class ‘PHPMaker2021\ur\HttpErrorHandler’ not found in C:\xampp\htdocs\ur\index.php:62 Stack trace: #0 {main} thrown in C:\xampp\htdocs\ur\index.php on line 62

I don’t think your composer update was successful. Did you see the “vendor” folder?

You may try:

  1. Delete composer.lock and “vendor” folder in the project folder,
  2. Generate all files (including composer.json) again,
  3. Open a command prompt or PowerShell at the project folder,
  4. Enter “composer -V” to test your composer installation, make sure there is no error message.
  5. Enter “composer update” to update. Then you should see a “vender” folder in the project file. In the “vendor” folder you should see many subfolders and an autoload.php.
  6. In the project folder, you should find a “src” folder, in which you should find the HttpErrorHandler.php.
    If the autoload.php is generated by composer correctly, your app should find the class HttpErrorHandler.

Thank you for your help,
already successful

I hope phpmaker will be more successful