Can't Pick Up Quest - Omens Unified

Other than the first week when you unlock Fractured Spark of Omens, there is a weekly limit of one Fractured Spark per week. This means you should only be able to create a Spark of Omens once every other week after that initial week.

If you miss a week of obtaining a Fractured Spark, you may be able to obtain additional sparks up to the weekly current limit through various world content. For details about this feature, you can read Wowhead's blog post.