Uninstalled reinstalled and then it wasnt working. The "dashboard" entity type did not specify a "default" form class.

Problem/Motivation

Drupal\Component\Plugin\Exception\InvalidPluginDefinitionException: The "dashboard" entity type did not specify a "default" form class. in Drupal\Core\Entity\EntityTypeManager->getFormObject() (line 209 of core/lib/Drupal/Core/Entity/EntityTypeManager.php).

Steps to reproduce

Uninstalled and reinstalled.

Proposed resolution

Added this to handlers saection of dashboard entity and fix the issue.

"form" = {
"default" = "Drupal\dashboards\Form\DashboardForm",