dhcpd.conf: option 66

Hello,

A VoIP system by Fanvil (business phone lines) requires an option 66 to be sent by dhcp to each handset. The option is a string containing an URL for provisioning.

> https://example.my3cx.com/provisioning/[key]

The following returns "fatal in dhcpd: Configuration file errors encountered."

> host example { [omissis]; option option-66 "https://[omissis]"; }

The dhcpd.conf manual, dhcp-options manual, and FAQ do not give directions.

This is hardly new, so how did you solve this puzzle and where do we read about it?

Thank you