SSH into server - Password changed

After I installed NextCloud onto my server it has changed my logon and password for SSH. Any idea what it could be? I tried the password that I use to log on as ADMIN to the NEXTCLOUD but that dont work. The password that I used to initially set up Ubuntu does not work. I have done this a few times and each time i install NextCloud it changes the ROOT password to something that I do not know. Any ideas?

Something like that is simply not possible. You are obviously drawing the wrong conclusions.
Apart from the fact that you should always configure SSH for key identification.

Of course not. It is on a complete other level, another server.

When you setup Ubuntu, you can, but normally do not give root a password. You create a user with sudo rights. Root normally do not have a password until you explicitly assign one.

Ok I have setup the server AGAIN. this time with a username and password on ununtu without root and the USER ID and password as soon as i run the setup portion thru the web browser the password changes for the UBUNTU SERVER SSH logon. Every single time. Not sure why but it just keeps happening. Totally fresh installs each time

As stated above this is not possible unless your using a 3rd party script that is not Nextcloud related.

If your so sure this is Nextcloud issue please provide logs of your installation setup and the tutorial or instructions followed from the manual.

ps. Why after so many failures do you not create a backup user with sudo rights.