Using WP All Import to import multiple checkbox values is a bit confusing because WP All Import on it’s own will upload the first value of multiple checkbox values, but won’t import the rest.
To import multiple checkbox values you need to buy the ACF Import Add-On Pro. If you bought the stand-alone WP All Import product you can buy the add on by logging into your Wp All Import account and going to the discounts tab: https://www.wpallimport.com/portal/discounts/
If you are importing multiple checkbox values from different columns in a spreadsheet, you will need to use the set with XPath option.
So, if your checkbox values are setup in your spreadsheet like this:
You will need to setup WP All Import to import the field like this:
You will find this option under the “Advanced Custom Fields Add-On” section when you are mapping the field to import in WP All Import.