Not working and strange behavior for admin menu

Hi, I am very interested in uipress, I was about to pull the trigger, but I have tried uipresslite and your customization of the admin menu does not work, it just turns it black and changes the logo, otherwise it stays with the standard wordpress look and feel. I am 100% sure that I have not configured it wrong because I have done many tests in the demo of your website and I know how to use it... I thought it could be a compatibility problem with another plugin, but with all deactivated except uipress, the same thing happens.

I have the site on Siteground, and I have another one, which has had very little life (should not have many “remains” of things out there), very few plugins installed etc and does exactly the same, I install it, in this case simply activate the option to use the modernized theme and .... I change the color of the menu on the left to black and change the logo, but nothing else...

I do not pretend that you do a technical service action, but more than anything is pos if you know something that explains this behavior.

I would not want to buy it and that it does not serve me for what I want....

Thank you.

Best regards