I have installed FreePBX on Xenserver with some success. I can place outgoing and receive incoming calls, I can register with Zoiper on my iPhone and Windows 10 desktop but I cannot get my extension on my Cisco SPA 303 phone to register. I am a newbie about this and don't find any info in the log that helps me identify the problem or even where it is.
I've put the relevant files in Dropbox so please take a look.