During the day our sites show a 404 error, some of these are found in two multisite sites (sitoalkilo.com and sitoalkilo.it) and normal sites and all show me the 404 error.
Dont create multiple topics for same issue. You have already created a thread for your issue at Error 404 of multisite - #20 by adrian
I apologize but I urgently need to solve the problem as I have clients who are pressuring me not to see their websites
Creating multiple topics for same issue wont give you speedy responses. You need to understand that this is a free project and the support too is free on the forum. You cannot pass on the pressure here with your acts. If you need instant help then you must hire someone to get this fixed asap by paying his/her charges.