Start the setup from scratch.

1. Disconnect the shift cable at the rear derailleur

2. Try shifting the rear derailleur by hand all the way to the largest cog while turning the crank by hand.

3. If it won't shift to the biggest cog, loosen the low limit screw until it will but not so far as to spill the chain inside. Let the derailleur relax and shift it by hand several times to be sure the shift is solid but not too far.

4. While turning the crank, let the derailleur relax to be sure it will shift solidly to the smallest cog with out spilling the chain to the outside. Adjust the high limit screw if necessary.

5. Repeat steps 3-4 several times to be sure the limit screws are correctly set.

6. Shift the brifter's inner lever multiple times to be sure it is in the highest gear position.

7. Reattach the cable to the rear derailleur and pull out all of the slack before tightening the bolt. Be sure the cable is attached to the proper side of the bolt.

8. Try to shift from the smallest cog to the second smallest. Use the rear derailleur's adjusting barrel as needed until the shift is quick and repeatable with no grinding on either side.

9. When the 1 to 2 shift is good, try shifting all the way across the cassette, including into the largest cog. It should work properly or with only very slight adjustment of the cable slack. Do not readjust the limit screws at this point as they are already set correctly.

If it still won't shift to the largest cog, either your brifter is defective or the derailleur hanger alignment is off.