Reply To: Unable to parse ini file: config/custom.config.ini

You need to determine which product numbers in the inventory table do not have a match to an id field value in the product table. If the product_id of an inventory record is wrong, change it to a correct value. If the inventory product_id should be for a product that is missing, you can add the missing product, get its id and then change the inventory record to the new product. Or you could delete the orphaned inventory record.

Sorry you have to go through this, but once fixed, the database will enforce foreign key settings to prevent future issues.