If you are attempting to use an AMI from another region, this error happens. The current marked answer saved me a lot of time in figuring out what the root cause was for me.

if you are using a data source to lookup AMI's you will need to create a data source for each region you need to lookup AMIs. If you are using a static list from a table, you will need to make sure your lookup has the AMIs for all possible regions and factors in the region in the lookup.

Hopefully that will be helpful context for someone. I do not have the reputation to add comments to the current answer or I would have.