I was able to reproduce the error on a freePBX 16 distro I just installed. This time I did not use the web-gui to update the modules, instead I did fwonsole ma updateall.
Yet, the error occurred again, once I enabled DPMA in EPM.
I had the same on FPX16 , I touched and chowned res_digium_phone_general.conf and it then loaded OK
But still having issues on this server as it wont build the DPMA config file in /etc/asterisk/dpma/phone-configs , its creates the directory but not the file there.
Getting
Failed to load the File. Error is captured in /tftpboot/DigiumLoadXmlFailedFiles/289-1/000FDXXXXXX.cfg DOMDocument::loadXML(): error parsing attribute name in Entity, line: 83