Problem

[DiegoLeon2018]

Hello everyone, I am having problems with Google Sheets, everything I write from AppSheet in data type (Date or Datetime) is being displayed like this and it returns an error therefore in AppSheet

[WillowMobileSys]

My guess is that on the sheet side, those columns apparently have formatting applied to them.  Change the column format in the sheet to basic DateTime format that is supported in AppSheet OR simply change it to general text.   You will then need to make adjustments to the existing rows column values manually, edit the rows and change the Dates in the app or delete the rows and insert again.