Deploying Algo vpn server with my existing droplet. Got error of permission denied..

[waltirus]

Hello there! I wonder if my error is typical. Is it possible at all to deploy Algo using the existing droplet with Digital Ocean? Why should I all the time create a new droplet (destroying the old one) when deploying Algo vpn server again. I had to reinstall my Windows and lost my previous settings with the existing droplet. I received the following error message at the end of the deployment scripting:
TASK [Wait 600 seconds for target connection to become reachable/usable] ************************************************************************************
failed: [localhost -> xxx.xxx.xxx.xxx. ] (item=xxx.xxx.xxx.xxx.) => {"ansible_loop_var": "item", "changed": false, "elapsed": 805, "item": "xxx.xxx.xxx.xxx", "msg": "timed out waiting for ping module test: Data could not be sent to remote host "xxx.xxx.xxx.xxx". Make sure this host can be reached over ssh: Warning: Permanently added '[209.97.181.40]:4160' (ED25519) to the list of known hosts.\r\nalgo@xxx.xxx.xxx.xxx: Permission denied (publickey).\r\n"}

(I blurred the IP address for security reasons). I generated the token for this droplet again and entered it successfully while deploying the algo vpn files. So, all the information provided was sufficient, I guess.
Can any one prompt me what is the reason for this error?