mycred_sell_this isn't working properly

Hi.

Have you followed the installation guide for the Sell Content add-on?
Is the sell content add-on enabled?
Did you go though the setup?

If the shortcode does not render, you have not enabled the sell content add-on.

oh im sorry, it my fault,
I enabled the gateway
but I can not see a button called “Buy”
i set the price for 100 and my balance is 10 o,o
https://gyazo.com/d6efb3b150eccd2425a19bd00f65bc6d
https://gyazo.com/c387c2b0924722c5b25d8d0b2d51d36a
please help ty

Remember that the post author and administrators can not buy posts. Make sure you are trying to buy using a regular account that is not the post author or an administrator.