Getting Jars of Fig Jam to Seal

l made six jars of Fig Jam (Jello type) today. All six jars failed to seal.

I washed and filled the jars with water, put them in microwave and brought them to boiling. I poured the boiling jam in a very hot jar and then cleaned the top of the jar with a clean wet cloth. The rings and lids were waiting in a pot of boiling water. I place the lid on the jar and put the ring on it, not too tightly. I left them on the counter top to cool and seal. They cooled but did not seal.

What am I doing wrong?

I'd like to do a repair job tomorrow. Can I reheat the jam in the microwave and try again? If so, please tell me how.

Thanks,
Trixie