Crypto Buying Power

I have a node application that trades both stocks and cryptocurrencies. I received a large number of 403 errors today for which I couldn’t understand. I had enough buying power and cash in the account to cover the trades but was still getting a 403 error. I just not logged into the GUI and tried to buy Bitcoin/BTCUSD and received an alert that my crypto buy power was drastically different than my account’s buying power or the cash on my account. I assume there is a formula for this but I can’t figure it out. It seems that crypto buying power associates with non_marginable_buying_power (whatever that means)

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