Ssh server requesting password

i generated ssh key from ubuntu 20.04 64bit guest machine inside virtual box running in Windows10 64 bit. i successfully registered my ssh key with my ubuntu one account. when i tried to ssh to my raspberry pi 3b it requested password.

are you trying to log in to your raspberry pi from the 20.04 VM where you generated the key (i assume this is the onl place where the secret part of your key exists so from there i should work) ?

yes i want to log from 20.04 where i generated my key

Is the pi running ubuntu core, and if so, on first boot did you enter the email for the ubuntu account for which you previously uploaded the public ssh key? That first boot part (console-conf) is what creates the user on the core device ready for ssh.

thank you, you are very correct,
for the first time i generated the key on another ubuntu so when i changed my pc machine i generated another ssh key , think that every time you ssh the server it check the public in ubuntu one account against on in the local .ssh folder.

so is there away i can re install my public inside the raspberry pi without reinstalling ubuntu core 18