Anti theft has been discontinued as far as I know best to call support and ask them about your issues
I will also ping a tech as AT is not used by we mods
Readiing similar posts with same error seems you do need tech support to fix this
To better assist with this issue, we suggest you to contact our support as this involves, verification of Proof of purchase, subscription extension etc..
Please see Specialized Services for Home and Home Office for the right phone number for your country.Select Antitheft support in the IVR option.