i.LON 100 e3 and i.LON IP-852 Router Activation

I am a technician and my duty is maintenance the BMS device, one of my site using i.LON 100 e3 as LON device Router and TAC Visita as BMS core software 6 years ago,
Recently, one of the i.LON 100 e3 not stable, alway turn to offline and only sometimes online, the web base services lagging & could not login.
I found a spare parts to replace, after configured the router, I find IP-852 Router LonTalk Side and IP side is "not licensed". Would I transfer the license from the abnormal i.LON 100 e3 to the spare parts i.LON 100 e3. If available, which link or form should I go and action, or have any suggestion, pls advice.