I can connect with SSH without password, using keys generated with Putty, when I do it within my LAN or using, also within my LAN, an address provided by no-ip. The strange thing is that when I try to SSH connect from outside, I cannot do it in any way except by using an android phone, with Termius or any other app capable of managing keys. In this case I can connect perfectly, but when I use Putty, Bitwise, Filezilla or even Termius in Windows, with the same key-pair, of course, I never succeed. I also tried with Putty and Filezilla installed in a Lubuntu OS and no success, either.
Has anyone had this problem and been able to solve it?