Can't move stop loss for shares AAPL

I’m trying to practice traiding with AAPL share, but after I make an order I’m not able to move the stop loss, the amount of shares is highlighted red … because the system thinks I’m over the margin limit, but I’m not making a new order, I’m just moving the stop loss (and my position is profitable)

Expected Result: user is able to move the stop loss for the current position without any issues.

Actual Result: user is not able to move the stop loss, if user took more than 50% of the account size position.