I received a "Notice of Proposed Assessment" from CA Franchise Tax Board saying that they have disallowed the carryover credit from my 2015 Ridesharing carryover of $728

I received a "Notice of Proposed Assessment" from CA Franchise Tax Board saying that they have disallowed the carryover credit from my 2015 Ridesharing carryover of $728 plus interest. What is this? What do i do? Can I contest it?