Answer by allo for SSH access denied when 'authorized_keys' file is created with Vim

Probably you pasted it wrong.

• Does it start with ssh-rsa or with ssh-ed25519?
• Does it have a space before (it should NOT)
• Is upper/lower case preserved?
• is there a space before any comment at the end of the line?

before pasting anything in vim, you should use :set paste, as it switches off any possible active autocompletion/autoindent/... macros.

Another thing is, that you wrote mykey.pem, which is the usual extension for openssl files, not ssh-keys. Are you sure, you used the id_rsa.pub / id_ed25519.pub as ssh-pubkey?