Hey @Josh2 , nice to meet you 
Are you still encountering this error? BundleValidationErrors occur when the bundle (set of data) entering the module doesn’t pass validation. Validation means that before processing a bundle in a module, Make checks whether data types match in the module mappings and whether there are no missing values in the module required fields.
Based on the screenshots you shared, it looks like the email value coming from MS 365 Excel doesn’t pass the validation standard of Sendlane. In my experience, it’s most likely to be an invalid domain value.
You might want to consider using some error handlers. Here’s a guide from Make that I always find useful - https://www.make.com/en/help/errors
I hope this helps!