Getting error on Save and Edit in model admin

Silverstripe Version: 5

Question: Hello, when I save the form data in the ModelAdmin (create or edit), I am getting this error:

[Emergency] Uncaught SilverStripe\ORM\UnexpectedDataException: Invalid Class ‘’ in ChangeSetItem #183

POST /admin/transactions-reoccurring/App-Model-TransactionReoccurrenceDef/EditForm/field/App-Model-TransactionReoccurrenceDef/item/3/ItemEditForm

Line 179 in /var/www/html/vendor/silverstripe/versioned/src/ChangeSetItem.php

I am new to SS. Am I missing any configuration in the model, AdminModel or a database table?
Thank you so much

// Include any relevant code. If you have a lot of code, link to a gist instead.

Hard to answer without seeing any code. My guesses:

  1. you did not run dev/build after modifying the model
  2. you have some kind of error in your model
  3. a model file has been removed