Transplanar Lock

You wave your hands in a warding motion, and after a moment release a mighty magical pulse. All portals in range are shunted into partial dormancy and become hazardous for travel, all creatures maintaining concentration on a portal in range must immediately make a Charisma saving throw or be affected by the spell. At the end of each of their turns, they must repeat the saving throw or drop concentration.

As an action on their turn, an affected creature can attempt to force the portal open. You must succeed on a Charisma saving throw against their Spell Save DC or they, and the portal(s) they are concentrating on are no longer affected by the spell.
As an action on your turn, you can attempt to shut the portal again. A creature of your choice concentrating on a portal within range must succeed on the Charisma saving throw or be affected by the spell again, having their portals shunt again and potentially dropping the concentration later.

During this time, any creature attempting to use a shunted portal must first succeed on a Charisma saving throw or the portal doesn't work, it also takes 4d8 force damage and is stunned for 1 round. On a successful saving throw, it takes half the damage and suffers no other effects.

Any portal that remains shunted for the whole duration is permanently closed and gone.
At Higher Levels: When you cast this spell using a spell slot of 5th level or higher, the range of the spell increases by 30 feet for each slot level above 4th.