An Item is marked as Inactive (Blocked) in the following situations:
- Item was closed because of the Amazon policy violation.
- Item was blocked by Amazon because of the wrong setup, i.e. a price was set to the wrong value.
- Item is incomplete, i.e. price value was not set at all.
To fix it, you need to adjust the Item information directly in your Amazon Seller Central. Once it is done, M2E Pro will synchronize the changes, and the Item status will be updated to the Active.