I was running 19.07.3 on my router, and I could easily ssh into the box using an SSH key. Now I upgraded to 19.07.5 and SSH is not working any more, neither using password authentication, nor using an SSH key.
I tried removing the package dropbear, deleting the provided public key, reinstalling dropbear, letting opk overwrite any existing file. Then I added a complete new dropbear instance, choosing password authentication and allowing root to login using password. Then I even changed root's password to "123456" temporarily, to eliminate any typing errors.
But still no deal:
ssh email@example.com firstname.lastname@example.org's password: Connection to 10.20.30.40 closed.
What is wrong in 19.07.5, compared to 19.07.3? Why does this dropbear version not accept any connection?
Once I accidentally hit ENTER without typing in the password, which leads to this dialog:
ssh email@example.com firstname.lastname@example.org's password: Permission denied, please try again.
So, typing in the password is closing the connection, while typing in no password is answered by "permission denied".
Can someone explain this?