You can definitely have cinnamon
At church a lady told me that Canela helps produce more breast milk. I tried it amongst other things. Not sure if it was exactly the canela that helped or a mix of everything else. But it def didn't hurt it.
I have actually seen people make abuelita’s hot chocolate with cinnamon and ginger to improve their supply! Not sure if that works or not but I doubt it hurts!
Not a direct issue with breastfeeding, but please look up recent lead levels in cinnamon. Most has high levels of lead, but you can find some safer options depending on the brand
I was drinking a cup of te de canela in the mornings for few days while breastfeeding and my baby girl (3 weeks) was just fine same with milk supply
I had no issue with cinnamon