Using Tools>Sketch Tools>Check Sketch For Feature. It says that the end points aint merged.
I deleted the radius. Drew a new one on the construction line. Made it coincident to the two endpoints. Applied the 19 dimension. Trimmed it and it worked on my end.
Hope this was helpful.
Have a great day!
Use the Contour option in the Extruded Cut tool, and selecte inside the loop.
Edit the sketch
Select the lower horiz' construction line
Delete the Distance4 constraint
The regular Extruded Cut will now work