Likely Robinhood doesn't normally trade OTC stocks, but making an exit only exception for this now OTC, formerly NASDAQ, stock? Have no experience with Robinhood, but have heard lots of complaints on other forums.
If you want to keep your shares of TRNX to trade, then consider transferring your brokerage account from Robinhood to Webull. You will get free shares for opening an account and also get to trade from 4 am til 8pm at no extra cost. Downside, might take 5-7 business days.