Error after updating to version 8.x-1.21

Hi,

I've updated to version 8.x-1.21. The following error happens:

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Got error 'PHP message: TypeError: Argument 1 passed to Drupal\\admin_toolbar_tools\\ToolbarHandler::arrayInsert() must be of the type array, null given, called in /var/www/vhosts/example.com/httpdocs/example/web/modules/contrib/admin_toolbar/admin_toolbar_tools/src/ToolbarHandler.php on line 62 in /var/www/vhosts/example.com/httpdocs/example/web/modules/contrib/admin_toolbar/admin_toolbar_tools/src/ToolbarHandler.php on line 128 #0 /var/www/vhosts/example.com/httpdocs/example/web/modules/contrib/admin_toolbar/admin_toolbar_tools/src/ToolbarHandler.php(62): Drupal\\admin_toolbar_tools\\ToolbarHandler->arrayInsert(NULL, 1, Array)\n#1 [internal function]: Drupal\\admin_toolbar_tools\\ToolbarHandler->lazyBuilder()\n#2 /var/www/vhosts/example.com/httpdocs/example/web/core/lib/Drupal/Core/Render/Renderer.php(358): call_user_func_array(Array, Array)\n#3 /var/www/vhosts/example.com/httpdocs/example/web/core/lib/Drupal/Core/Render/Renderer.php(195): Drupal\\Core\\Render\\Renderer->doRender(Array,...\n', referer: https://www.example.com

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What can it be?

Thanks.