It is the code for changing the cipher text from a plain text in cs50. I have tried with test case and it is giving the correct solution however when I try to use the cs50 checking command it shows an error which is out of my understanding. Can you guys help me with it? I am trying to find the error and what is causing the solution to be wrong.

This is my code

    #include <cs50.h>  
    #include <ctype.h>  
    #include <stdio.h>
    #include <stdlib.h>
    #include <string.h>

    bool check(string num);

    int main(int argc, string argv[])
    {
        // check if the command-line-argument is 2 characters
        if (argc != 2)
        {
            printf("Invalid Keyn");
            return 1;
        }
        else
        {
            string num = argv[1];
            if (check(num) == true)
            {
                int key = atoi(num);
                string ptext = get_string("Enter plain text:");
                for (int i = 0; i < strlen(ptext); i++)
                {
                    if (isupper(ptext[i]))
                    {
                        printf("%c", (ptext[i] - 65 + key) % 26 + 65);
                    }
                    else if (islower(ptext[i]))
                    {
                        printf("%c", (ptext[i] - 97 + key) % 26 + 97);
                    }
                    else
                    {
                        printf("%c", ptext[i]);
                    }
                }
                printf("n");
            }
            else
            {
                printf("Usage: ./caesar keyn");
                return 1;
            }
        }
    }

    // check if the key is all digits
    bool check(string num)
    {
        for (int k = 0; k < strlen(num); k++)
        {
            if (!isdigit(num[k]))
            {
                return 0;
            }
        }
        return 1;
    }

I keep getting this error message when it is actually showing the same results as it should be. I don’t understand what to do please help me.

    Results for cs50/problems/2024/x/caesar generated by check50 v3.3.11
    :) caesar.c exists.
    :) caesar.c compiles.
    :( encrypts "a" as "b" using 1 as key
        expected "ciphertext: b...", not "bn"
    :( encrypts "barfoo" as "yxocll" using 23 as key
        expected "ciphertext: yx...", not "yxoclln"
    :( encrypts "BARFOO" as "EDUIRR" using 3 as key
        expected "ciphertext: ED...", not "EDUIRRn"
    :( encrypts "BaRFoo" as "FeVJss" using 4 as key
        expected "ciphertext: Fe...", not "FeVJssn"
    :( encrypts "barfoo" as "onesbb" using 65 as key
        expected "ciphertext: on...", not "onesbbn"
    :( encrypts "world, say hello!" as "iadxp, emk tqxxa!" using 12 as key
        expected "ciphertext: ia...", not "iadxp, emk tqx..."
    :) handles lack of argv[1]
    :) handles non-numeric key
    :) handles too many arguments
    To see more detailed results g