Problem with overlaying logo

I’m having a problem with a logo overlaying a surface that I can’t get it to work properly. As you can see from the picture, the logo is a png image with alpha channel and I used the specific node set up that you can see in the picture. However it seems that the border of the png is still apparent and it gives a distinct uneven tone to the surface.

I’m sure that it’s pretty obvious to fix, however I’m stuck and I can’t get to find a solution no matter how obvious it may be.
Any help would be greatly appreciated.

Thanks in advance

By the looks of it, the png alpha isn’t completely 0, or it is but the thing is using separate materials. Cropped screenshots and no example .blend means limited information about the setup so I won’t waste time with other guesses.

Could you not insert a math node between the alpha and mix slot - use “greater than” to force the alpha channel values to 0 and 1.

Thank you guys!

It was that obvious after all and I was just that stuck to notice! :o
It appears that the png alpha wasn’t completely 0, so I adjusted it and now everything’s fine.

Thank you for your time!