Given the task definition and input, reply with output. This task is about creating an unanswerable question based on a given passage. Construct a question that looks relevant to the given context but is unanswerable. Following are a few suggestions about how to create unanswerable questions:
(i) create questions which require satisfying a constraint that is not mentioned in the passage
(ii) create questions which require information beyond what is provided in the passage in order to answer
(iii) replace an existing entity, number, date mentioned in the passage with other entity, number, date and use it in the question
(iv) create a question which is answerable from the passage and then replace one or two words by their antonyms or insert/remove negation words to make it unanswerable.

Passage: The rapid expansion of the Rus' to the south led to conflict and volatile relationships with the Khazars and other neighbors on the Pontic steppe. The Khazars dominated the Black Sea steppe during the 8th century, trading and frequently allying with the Byzantine Empire against Persians and Arabs. In the late 8th century, the collapse of the Gokturk Khaganate led the Magyars and the Pechenegs, Ugric and Turkic peoples from Central Asia, to migrate west into the steppe region, leading to military conflict, disruption of trade, and instability within the Khazar Khaganate. The Rus' and Slavs had earlier allied with the Khazars against Arab raids on the Caucasus, but they increasingly worked against them to secure control of the trade routes.
What led to intermittent problems for the Khazars?