Timeout error - generic

I am running a new Erpnext v11 installation. I have easily carried out various mass imports of photos, articles, documents … and invoices.
Now when I go to the panel and start working, I create, modify and delete documents but shortly after either updating a link or opening a new one I get a “timeout” error and then I see a blank page in the open or updated link.
I tried to vary the timeout parameters from 120 to 300 (500, 1000 and 3000) but having had no improvement I returned them to their original value.
I don’t understand what this “timeout” is determined

If you’re importing via xlsx files, the system can sometimes give some errors and/or take a long time.
BKM helped me last week with some pointers in this post - basically if you change to CSV files, your life becomes much easier

I thank you for the prompt intervention, but I solved the problem a little while ago.
It was due to an external factor. In fact the network manager “Vodafone” had and still has a central problem, therefore it succeeded in distributing a minimum of insufficient traffic, therefore data interruptions occur.
To solve the problem, I had to limit and distribute the network loads up to the resolution.
I thank you and salute you.