Summary
In order to make definitions between the seller and marketplace's catalogs compatible, categories, brands and specifications have to be mapped.
Marketplaces cannot export the sellers’ brand template to map brands when the number of brands listed by sellers exceeds the Excel maximum limit.
Simulation
You can reproduce this error in the VTEX Admin by accessing: MARKETPLACE > Sellers > Categories and brands. Then, in the Brands mapping field of the seller with the most brands, click on Download current mapping table. Instead of receiving the Excel file by email, you will receive an email with the following message "Error exporting Brands Mapping spreadsheet".
Workaround
When this situation occurs, brand mapping cannot be performed. We suggest that marketplaces manually select the brand when cataloging SKUs on the Received SKUs page.