I just checked it myself and have it also in my environment. So it’s something from Tryton itself, but it doesn’t influence the rest because for me it’s working.
A simple check if the web part is working is just putting an index.html into the directory which you specified in your trytond.conf. So look at your trytond.conf under the section web. Below an example:
[web]
listen = 192.168.1.10:8000
root = /home/tryton/testtryton/www
The root is the location where your index.html should go. Also check the permissions!
If the above works. you will see the content of your index.html. Now you can put all the Sao data into that location, check the permissions and try again.
To install Sao in a easy understandable way check Setup web client with Debian 10 - #63 by edbo