I am facing this issue even when there is no issues in my data when i look over in the columns section. can anyone help me out.
Maybe this post will help, seems having similar error notification?
From the error, it is understandable that there is mismatch between number of columns in database vs number of columns in Appsheet.
Try regenerate structure option for JUNE 20 table couple of times and reconfirm.
Also if you are using Cloud MYSQL database, check in data base triggers whether column names passed correct or not