Everything worked ok for a while but now I can not get a connection from desktop to printer inside LAN environment.
I do have a fully functioning Octoremoto WAN connection port forwarded to LAN IP adress and all.
For all we know, they may have additional security and know what they are doing. The warning is still relevant, especially as there is no extra detail.
Thanks for all the suggestions but I have managed to get it functioning again.
Using Advanced IP Scanner I was able to not only confirm the LAN IP adress was correct and active but also to log in into Octopi. After that I again made sure the LAN IP adress was fixed in my router and that did the trick. So all ok for now.