There are many possible reasons why your listing isn't repricing.

1. Missing repricing rule, Min Price or Max Price.
2. Repricing Paused
3. Check repricing rule.
4. Min Price = Max Price.
5. Listings with No Competition won't receive an SQS notification from Amazon.
6. Missing Amazon SQS notification. It will take 12 hours for automatic repricing. 
7. Inactive listings do not reprice.

Rule Based Common causes

1. When you win the Buy Box and your Buy Box setting set to Do Not Change My Buy Box Price.

2. Competitors are below your Min Price. (If the corresponding price adjustment strategy is set for "Do Not Reprice," the listing won't proceed to reprice. )

3. Competitors are above your Max Price. (If the corresponding price adjustment strategy is set for "Do Not Reprice," the listing won't proceed to reprice. )

AI Rule Common causes

1. Your rule setting Do Not Reprice is applied when your product is backordered.

2. The price does not need to be adjusted after estimation by AI.