I can't update firmware in my Unifi Dream Machine using ssh

I am most grateful for your response, but my understanding of your response is almost zero. I am new to this stuff. I previously had a Unifi USG and had no difficulty in entering simple ssh commands on the advice of others, but it seems the UDM has a different security structure.

I will attempt to answer your questions

• Is the UDM configured to allow an SSH connection. I believe so. I enabled it and set username and password. I have an access point at 192.xxx.x.x and entered this in my iMac's Terminal ssh admin@192.xxx.x.x. This allowed me in to the AP by ssh. But when I entered ssh admin@192.xxx.x.y the response was "Permission Denied" due to incorrect password. Other forum responses suggest that the UDM has its own security. I don't know what it is.
• Is the UDM configured to allow connections from your Mac and the Mac's IP/DNS Name How do I check this?
• Does the UDM's SSH connection allow passwords or must you access the UDM using keys? The UDM does allow passwords to be set, but whatever I enter does not work when I use the UDM's IP address, only other devices attached to the UDM
• Are you providing the correct user name and port number for SSH? I'm not entering port number (which I believe is 22). The user name I entered when I enabled SSH, but when I use the UDM IP, the response is "Permission denied"
• Sounds like the problem is with the UDM and its configuration. My UDM is less than a month old, in the hands of a newbie. I have enabled SSH and set user name and password. What else can I do?
• I have no third party software on the iMac which I have owned since early 2013. No anti-virus, third-part security or firewall. Only stock-standard MacOS out of the box, always updated except for Big Sur. (iMac is too old)

Some of you techies say things like "Just ssh into your hardware and enter these settings" but I'm not in a state to do that with the apparently locked-down UDM.

I'm keen to get to the bottom of this, and as you were kind enough to respond, I would appreciate some tips and tricks to get past first base.

Regards

Thanks for the kindness in responding

I just cracked it.

In the UDM where I enabled SSH, I was asked for a user name and password. I Say I entered "fred"as username and "pwd0410e" as password, the correct syntax in the iMac's Terminal is

ssh root@192.xxx.x.x

and when requested for the password, I entered "pwd0410e" and got this...

The use of "root" and the password defined when setting up SSH in the UDM is nowhere to be found in easily discovered documentation.

So whew, I got there.

Thanks again for your assistance. Gratefully accepted

Regards