While the vaporization of the Holy City of Jedha by the Death Star is not quite the apocalyptic event that was once feared, the damage to the planet is wide ranging and long term. While the Empire was committed to extracting as much kyber in Jedha as possible for the development of their superweapon, kyber is a living crystal and small pockets are constantly forming. Hit with a superlaser and ejected into the atmosphere the microscopic dust scattered within the atmosphere plays havoc. Interplanetary communication has been rendered next to impossible, necessitating routing through a single orbital station. Intraplanetary comms have been jury rigged through multiple routers on the planet, but has provided a limited sensor net.
In spite of, or rather because of this difficulty, this has made new settlement of Jedha desirable for multiple reasons: first, those in black or gray market industries such as smugglers, mercenaries, theives and those who in general don't want to be found have used this blackout to their benefit, knowing that once a ship enters the atmosphere or through a stormy area that their signal becomes effectively untraceable via conventional methods.
As the kyber is living and attuned to the Force, this disruption does not hinder and sometimes may even help with those communicating or seeking through the Force.