hello alexandre btw this is a greek name 
good day alexandre btw that is a famous greek name !
so i have 1 server with ubuntu 20.4 server installed the nextcloud and 1 more server ubuntu 20.4 server installed onlyoffice via snapd from here Installing ONLYOFFICE Docs for Linux from snap package - ONLYOFFICE
i have made the onlyoffice https from the commands given i have installed the connector for newcloud of onlyoffice i have input the correct data for the connection and i can create edit files etc as root.
Now my problem is this then i log out from root and use an other user to connect eg beta from the same browser (firefox) i can edit create files etc, but when i use it from an other browser i get the error ONLYOFFICE cannot be reached. Please contact admin
Now 1 more test from an other browser eg chrome i ender nextcloud with user beta and i get always the same error meaning the above.I create a new user and i get the same problem again.
i have to mention that al the setup is inside an intranet(my lan network)
now photo ex1 is me as root opening a file
now ex2 is me an user beta on the same browser firefox opening a new file
ex3 is the beta user in chrome trying to open a file
does it make sense at all to you? also which exacly logs you need from /var/snap/onlyoffice-ds/112/var/log/onlyoffice/documentserver cause there are corverter ,docservice,gc,metric,nginx,error.log