Locate the cord lock mechanism in the headrail the lift cords run through this.
Roller blind pull cord stuck.
Different size blinds require specific cord widths.
If this does not solve the problem take the blind out of the window.
To rethread a roller blind rope cord start by removing the blinds from the wall and popping out the clutch which is the case with the cord in it.
Sometimes a pull cord for a blind gets stuck needing repair or breaks requiring replacement.
First hold the lift cords level with the headrail and gently pull.
Then make a 1 inch loop with the cord hold the clutch with the base facing down and slide the loop under the guard until it comes out on.
Pull down the blind to check the spring action leaving the blind in the mounting brackets.
If you ve ever pulled the chain in the wrong way it can lead to stuck the chain inside the plastic wheel and eventually pops off the mechanism so no longer you can control your roller blind with the chain.
If the shade hangs loosely from the roller or unrolls quickly without resistance the spring is too.
Pull the cord all the way to the level of the headrail or header piece which is usually stiff plastic at the top of your blinds.
You will see a pin.
Fortunately these are also easy to fix.
Gently pull on the cord.
Roller blind repairs roller blinds are operated via a simple chain system.
This should release the cord lock.
And since different styles of blinds might have their own.