Asset "RGTI" cannot be sold short

Alpaca Trading
1

Hi,

when I try to short the stock RGTI i get the following response:
{‘code’: 42210000, ‘message’: ‘asset “RGTI” cannot be sold short’}

I understand that RGTI is not on the easy to borrow list, but why is this the case? RGTI has a high volume, substantial number of shares available to borrow and a moderate borrow fee. Or am I missing something?

Thanks in regards.