Issue

You tried to change a modern SharePoint site's theme from Change the look feature, but the theme is not reflected on your site.

Reason

To apply your Theme Builder customization, ShortPoint inserts a stylesheet in modern sites. This stylesheet is using your configuration to override the default SharePoint styles. 

Solution

If you would like to apply colors via SharePoint Change the look feature, you have to reset your Modern Theme Builder customizations. This will remove all ShortPoint customizations from the site.

Follow the steps below to reset the Theme Builder settings:

Step 1: Open ShortPoint Dashboard

Go to the Site contents and open ShortPoint Dashboard from there:

Step 2: Open the Theme Builder

From the ShortPoint Dashboard page click the Theme Builder:

Step 3: Reset the modern customizations

Under Modern Theme section on the right side, click Reset to original site settings (modern) button:

That's it. Changing themes from the modern Change the look should now work as expected.