I don't know, maybe some newer vehicles of 2010 and up have higher security and the MK808 is not capable. Did you check function viewer of listed capability for your model and year Infiniti? Other than the dealer giving you the 4 digit PIN code or at least confirming what you tried to be correct or not (with proof of ownership of car and photo ID),  See what other 5 digit number combinations exist on the BCM label that you can try to convert to a 4 digit PIN# to try. Other than that I need to make make sure my IM508 tool is connected to internet and within it's update period when an internet connection to Autel's server is required for certain types of immobilizer key programming.

  Given the sometimes Hit or Miss capability of Price Point Diagnostic Tablets from China that are advertised  as a near do it all type of dealership tool, I have learned to be very skeptical especially if you can't add a key without erasing all working keys as part of the procedure. Just make sure you or your customer has AAA towing or you're doing the procedure in the dealership service parking lot. :-))

 "Where is the function viewer/ capability list? '

If you click on your function viewer app of your tablet providing you are within update period or the Autel coverage link below and select your tablet and the make model year of your vehicle and you do not see "All Keys Lost" listed under the module , then it likely doesn't have the capability to do the key programming if you cleared all the keys even if it might have the capability to erase all keys. LOL. It seems like I've had more luck with Nissan with Autel by selecting some models manually , entering the VIN and there are like 3 menu options to go into that I forget the names and I select the far right one of the 3  "By System" or something like that.

https://www.auteltech.com/vehicle-coverage/coverage2