Issues with ACME SFTP Upload Automation to Ubuntu server

[mightyi]

I have moved my Let's Encrypt and Dynamic DNS duties to Opnsense; and have both of these working fine.

I have set an automation task up to upload the certificate to my Ubuntu server via SFTP task; this then rebuilds the certificate into a full chain and makes it available via a network share to other machines to access for SSL services.

this used to work, but i've since replaced my Ubuntu server and installed Ubuntu 20.  no matter what i try to do, I cannot get them to talk.  I have set up an sftp user on the ubuntu server and have connected rom the opnsense shell and accepted the encryption key; but when trying to connect through the GUI process, it always fails to connect with an access denied issue due to the encryption key.

I've gone through loads of different guides, all saying something different, but no definitive guide on connecting Opnsense Acme task with ubuntu.

Please can someone point me in the right direction before i tear my last few hairs out..?!

[PotatoCarl]

After April ACME.SH completely stopped working for me, but I might help you with your issued: Please check if RSA keys are still active. I have seend with other installations that in newer distributions RSA keys might not work anymore.
So checking .ssh/authorized keys and in /etc/sshd/sshd_config check if the keys are still accepted. Likely, you can just not log into the Ubuntu host. Otherwise I'd recommend to create a special account for copying the files and a cron job to detect and move the files.