Error Message in "Assigned To" Column showing missing info

I am using a powerapp form on my list and all the fields were working fine and perfect!

I tried to change the "Assigned To" field to accept multiple users and then updated the form, but the auto email flow that I was using did not recognize the multiple user field so I turned it back as it was a single user field. Now when I am assigning any user and saving the form, it shows me "Required Info" in the "Assigned To" column and I am not being able to find any fix for this!

I have uploaded a screenshot for that error 

Any solution?