I'm a premium user. When I add tasks from my iPhone they are not syncho'g with todoist.com or Chrome app. Works the other way however and I receive push notifications.
Please try logging out of the app, and back in again. If this does not help, an un-install and re-install of the app could.
Are there any special details about the tasks that are not syncing, or is it anything you create on the iPhone?
Fixed. Thank you.