Amazon’s marketing portal for merchants crashes, disrupting Prime Day Sale

Amazon.com Inc.’s marketing portal for merchants crashed Tuesday night, according to multiple Amazon sellers and consultants, fouling up one of the online retailer’s biggest sales of the year.

The advertising portal is a self-service system where merchants and brands can adjust their ad budgets and bid on key words so their products appear in response to consumer queries. Without that online interface, brands are flying blind with their ad spending on Amazon.