The image you put out says that the deposit came from risky source and they are not even saying you are doing anything wrong with the affiliate. As per the image you posted they say that the deposit funds are deemed suspicious because they might have used in Darknet, mixed coins or even stolen funds. You need to get the response from them.
I never had any idea about gambling sites citing issues for using mixers

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I don't have sure, but all my deposits come from Binance.