How do I enter the unused RRSP contributions in my Schedule 7 on line 18 to record the RRSP contributions made this year but not claimed under RRSP deductions. I would like to carry ti forward to the next year. I tried to enter the amount on line 18 of Schedule 7 but it does not let me. WHat is wrong?

I tried to ask Turbotax but the phone system but it doesn't let me connect to anyone. IT is not very helpful at all.