Raspberry Pi 2 as a server. . .

I have a question. . .
I have a Raspberry pi 2 as a server. . .
On my laptop, I am running Ubuntu 16.04 LTS. . .
I can access the server with no problem at all. .

On my other laptop, I upgraded to Ubuntu 20.X LTS (can't remember the X).
Now I cannot access the Pi server. . .

I have researched and I have tried the following on the server:

client protocol = CORE
client protocol = NT2

Neither would allow my Ubuntu 20.x access the server.
How can my Ubuntu access the server again?

I did do a update on the Samba, and it said it was the latest
version.