Someone posted the same problem I think at least less than 10 pages back from here. I forgot the content of the post you may backread if you want.
I had the same problem when I joined first here. Im using mobile that time. I think it's on hidden character copied thru my browser. The signature will be ok but in bot it cant found. So to fix that I use desktop to logged my accoubt then copied the code correctly then evrything goes fine now.
That's the weird thing here. I did copy the right code. Just look at my signature.
█████ B I T M I X E R . I O ██ ██ H I G H V O L U M E B I T C O I N M I X E R ██ ██ B I T M I X E R . I O █████
█████ B I T M I X E R . I O ██ ██ H I G H V O L U M E B I T C O I N M I X E R ██ ██ B I T M I X E R . I O █████
█████ B I T M I X E R . I O ██ ██ H I G H V O L U M E B I T C O I N M I X E R ██ ██ B I T M I X E R . I O █████
do you copy the code using your desktop? ive experience the same thing in the past when i copy a signature code exactly using mobile it has some hidden characters