unblock
v. B2 Upper Intermediate UK //ʌnblˈɒk// un·block
v. to remove something that is stopping a flow of liquid, air, or traffic. It can also mean to allow a person or website to be used again after being blocked.
v. to remove an obstruction from a passage or channel, or to restore access to a previously restricted resource. Transitive — requires a direct object.
You need to unblock the drain to stop the water from spilling.
The technician had to unblock the server to allow the employees to access the internal database again.
After the heavy snowfall, the city crews worked through the night to unblock the main thoroughfare and ensure that emergency vehicles could reach the hospital without delay.
From un- + block.