Reinforcement capacity

So I’ve recently upgraded to castle level 37,
And I have an issue with my reinforcement
Capacity when I’m launching rallys, whether
Its red guards or otherwise, my capacity is
1.6 million which is incredibly low
For example one castle in the alliance is
Castle level 28 and their capacity is higher
Than mine, all buildings are currently at level
36, most research is complete
Anyone have any ideas as to what the problem
Could be?
Many thanks