problem connect onlyoffice documentserver with public ip

good morning, I have installed ucs onlyoffice with owncloud in a virtual machine, I configured it with fixed ip, later
I have configured a domain addressing the public ip of my router which I have configured the nat to address the fixed ip of the installed ucs, I have no problems when I access the owncloud in my lan network and I have been able to edit a file in onlyoffice, the problem arises when I access owncloud from wan with my public ip domain and when I try to open a file to edit with onlyoffice I get the error message: onlyoffice cannot be accessed, please contact admin.

I would appreciate the help since I am new to these applications.

access network lan
access network wan

Please check the onlyoffice-settings in Owncloud.

If you call from external the address
you should get a welcome page