I had the exact same issue in 2019 when I was commuting. Was called in for interview after qualifying for dropbox. It's system generated so there is not much you can do at your end. I had to wait a month and a half before getting an interview. My employer thankfully let me work from home. If you have a valid H1b visa that you will be renewing for the additional 3 years, it may likely be cancelled without prejudice. In that situation you just will have to wait to get an appointment. I'm not aware of the walk in process H1bissue is suggesting. Maybe that is an option too.