Selling Fractional Shares I have position in

I tried to sell a fractional shares on a stock that I have position in (so it shouldn’t be shorting), but I got the error ‘fractional orders cannot be sold short’. I tried to do the same thing in the web interface instead of the API and i got the same error. I tried to directly liquidating my shares using the (x) button, but it says ‘Failed to liquidate position in XX, position not found: XX’, XX being the ticker. It happened for many stocks.
It happened in the after hours if that is related. I expected it to create the order and complete it during trading hours tomorrow but instead it just gave me the above errors.