The fact that the screen comes up on a client XO suggests that the server
is configured correctly.
Build 852 is a very old build. I looked in sugarlabs.org activities browse,
to see if there were any newer Browse versions that work with sugar .84.
It does not look to be the case.
I suggest loadi
It sounds like the server is working, but we need more information about how
the xos connect and are configured.
First, from a browser on the xo does http://schoolserver.lan return the portal
screen?
If not, I suggest that Martiny have a look at
https://github.com/XSCE/xsce/blob/master/docs/INST
