Can you provide the make/model of the reader?
A photo of the reader and fob/card would help.
Do you have any diagnostic tools, such as the xFD or Diagnostic card?
Can you try scanning your fob with TagInfo?
whether this works or not, it narrows down an answer.
Your thread title is “household fobs”, so if you own the lock, this also makes things easier.
It is easier to enroll than copy*
Sniffing is generally used when you don’t own the lock, like a hotel for example.
It uses a tool such as the iCopy, like a “man in the middle” between
READER - iCopy - AUTHORISED CARD
*there are exceptions