Your import action is using "Combination of property" option to upload the file into the list.
I hope your loading a file through an action?
You getting this error, because of Column name different in your file vs Column name used initially to create this action, There is something incorrect in your template(might be the column name change or column change)
I have created an import action to load data into the list using this below template(File 1)
Now I am loading below file 2 into the list using the action.
AM getting this error, because there is different in column name.
Check the import file and compare it with the import action
Please review the data load process and try to find a unique key (code) instead of using Combination of Properties due to performance reasons. Please see the below article which details why combination of properties should not be used: