DownDetector reports that a number of users are reporting outages on the system:

But perhaps more troublesome, it appears there are issues with money transfers, vis Robonhood's status page:

Investigating - We're investigating reports that some customers are experiencing issues transferring money in and out of Robinhood. We're working to resolve this as soon as possible.

The outages and the money transfer blockage appears to have coincided with the crash in Tesla shares.