How to get Photoshop Fill tool to work properly??
In Paint Tool Sai, if I use the fill bucket tool, it fills it in perfectly. But when I try in Photoshop, I keep getting this annoying white outline

But seriously, how do I get it to work properly?? Even FREE drawing apps for my phone can get this right, but a professional tool can't?? Sorry this just baffles me, I try to adjust the tolerance, but it doesn't do anything.
If I google it, I only get answers like "You just don't know how to use it" which is like OK but tell me what I have to do?? I would use another app But I need Photoshop for the other features it has. Please let me know what I'm doing wrong. Thanks
