XF 2.1 rebuild cache issue

[sandokloud]

hey i recently have try to start a rebuild cache and when i was almost for done the crone screen blanck and see this issue:

An exception occurred: [XF\Db\Exception] MySQL statement prepare error [2006]: MySQL server has gone away in src/XF/Db/AbstractStatement.php on line 217

1. XF\Db\AbstractStatement->getException() in src/XF/Db/Mysqli/Statement.php at line 196
2. XF\Db\Mysqli\Statement->getException() in src/XF/Db/Mysqli/Statement.php at line 39
3. XF\Db\Mysqli\Statement->prepare() in src/XF/Db/Mysqli/Statement.php at line 54
4. XF\Db\Mysqli\Statement->execute() in src/XF/Db/AbstractAdapter.php at line 94
5. XF\Db\AbstractAdapter->query() in src/XF/Mvc/Entity/Finder.php at line 1261
6. XF\Mvc\Entity\Finder->fetchOne() in src/XF/Repository/UpgradeCheck.php at line 39
7. XF\Repository\UpgradeCheck->getLatestUpgradeCheck() in src/XF/Admin/App.php at line 238
8. XF\Admin\App->renderPageHtml() in src/XF/App.php at line 1989
9. XF\App->renderPage() in src/XF/Admin/App.php at line 122
10. XF\Admin\App->renderPage() in src/XF/Mvc/Dispatcher.php at line 362
11. XF\Mvc\Dispatcher->render() in src/XF/Mvc/Dispatcher.php at line 53
12. XF\Mvc\Dispatcher->run() in src/XF/App.php at line 2178
13. XF\App->run() in src/XF.php at line 390
14. XF::runApp() in admin.php at line 13

please help me how fix this issue!