Error while updating a list - Using SharePoint O365 with NWC

Hi @LoveNintex 

1. You stated "My connector is able to Retrieve the item with no issues."
   Just to clarify, did you meant you can retrieve the Lists or that your can retrieve a specific item from the list.


2. When you use SharePoint Online - Update Items action, caution is recommended as this action will act on the entire list. 


3. You must use the Condition to filter the items in which to update. Otherwise, the entire List Items will be updated. e.g. You meant to update the status "completed" for the condition where Item ID == 5, if you omitted the condition then the Update Items action will update every item in the list with the status "completed"


4. Your issue is probably due to a incorrect Condition. 
   Without knowing what was specified in the Update Items, its probably difficult to resolve your issue.


5. Are you using any variables in the condition?
   I would recommend to use fixed or hard coded (not variable) to check if the Update Items will work successfully.


6. Once the Update Items work, then replace back with your variables.
   If the variables do not work, then you need to check what is wrong with the variables using the Log action.