R is case sensitive so very likely the function is reliability() (whiteout the upper case).
If you need more specific help, please provide a proper REPRoducible EXample (reprex) illustrating your issue.
R is case sensitive so very likely the function is reliability() (whiteout the upper case).
If you need more specific help, please provide a proper REPRoducible EXample (reprex) illustrating your issue.