When I Inject my dll using this c++ console application it just seems to crash notepad. I’ve checked this other one which is having the same old issue but I cant really figure it out on my code because I dont want to break much but heres my code.

EDIT: I fixed the shell code to 64 bit, I hope but Ask me if you need the old 32 bit code because this is a 64 bit console app. But now I have an error that says It cannot open a handle to the process now

#include <Windows.h>
#include <TlHelp32.h>
#include <string>
#include <stdio.h>

using namespace std;

#pragma comment(lib, "ntdll.lib")

extern "C" NTSTATUS NTAPI RtlAdjustPrivilege(ULONG Privilege, BOOLEAN Enable, BOOLEAN CurrentThread, BOOLEAN* Enabled);

#define SE_DEBUG_PRIVILEGE 20

unsigned char shell_code[] = {
    0x50,                               // push rax
    0x53,                               // push rbx
    0x51,                               // push rcx
    0x52,                               // push rdx
    0x56,                               // push rsi
    0x57,                               // push rdi
    0x55,                               // push rbp
    0x41, 0x50,                         // push r8
    0x41, 0x51,                         // push r9
    0x41, 0x52,                         // push r10
    0x41, 0x53,                         // push r11
    0x41, 0x54,                         // push r12
    0x41, 0x55,                         // push r13
    0x41, 0x56,                         // push r14
    0x41, 0x57,                         // push r15
    0xE8, 0x00, 0x00, 0x00, 0x00,       // call next
    0x5B,                               // next: pop rbx
    0x48, 0x83, 0xEB, 0x06,             // sub rbx, 0x06
    0x48, 0xB8, 0xCC, 0xCC, 0xCC, 0xCC, 0xCC, 0xCC, 0xCC, 0xCC, // mov rax, 0xCCCCCCCCCCCCCCCC
    0x48, 0x8D, 0x93, 0x22, 0x00, 0x00, 0x00, // lea rdx, [rbx + 0x22]
    0x52,                               // push rdx
    0xFF, 0xD0,                         // call rax
    0x41, 0x5F,                         // pop r15
    0x41, 0x5E,                         // pop r14
    0x41, 0x5D,                         // pop r13
    0x41, 0x5C,                         // pop r12
    0x41, 0x5B,                         // pop r11
    0x41, 0x5A,                         // pop r10
    0x41, 0x59,                         // pop r9
    0x41, 0x58,                         // pop r8
    0x5D,                               // pop rbp
    0x5F,                               // pop rdi
    0x5E,                               // pop rsi
    0x5A,                               // pop rdx
    0x59,                               // pop rcx
    0x5B,                               // pop rbx
    0x58,                               // pop rax
    0x68, 0xCC, 0xCC, 0xCC, 0xCC, 0xCC, 0xCC, 0xCC, 0xCC, // push 0xCCCCCCCCCCCCCCCC
    0xC3                                // ret
};

void get_proc_id(const char* window_title, DWORD& process_id)
{
    GetWindowThreadProcessId(FindWindow(NULL, window_title), &process_id);
}

void error(const char* error_title, const char* error_message)
{
    MessageBox(NULL, error_message, error_title, NULL);
    exit(-1);
}

bool file_exists(string file_name)
{
    struct stat buffer;
    return (stat(file_name.c_str(), &buffer) == 0);
}

int main()
{
    LPBYTE ptr;
    HANDLE h_process, h_thread, h_snap;
    PVOID allocated_memory, buffer;
    DWORD proc_id;
    BOOLEAN buff;

    THREADENTRY32 te32;
    CONTEXT ctx;

    char dll_path[MAX_PATH];
    const char* dll_name = "DLL64.dll";
    const char* window_title = "Untitled - Notepad";

    te32.dwSize = sizeof(te32);
    ctx.ContextFlags = CONTEXT_ARM64_FULL;

    RtlAdjustPrivilege(SE_DEBUG_PRIVILEGE, TRUE, FALSE, &buff);

    if (!file_exists(dll_name))
    {
        error("fatal error", "DLL does not exist");
    }

    if (!GetFullPathName(dll_name, MAX_PATH, dll_path, nullptr))
    {
        error("fatal error", "Cannot get Full path name.");
    }

    get_proc_id(window_title, proc_id);
    if (proc_id == NULL)
    {
        error("fatal error", "Failed to get proc id.");
    }

    h_process = OpenProcess(PROCESS_ALL_ACCESS, FALSE, proc_id);
    if (!h_process)
    {
        error("fatal error", "Cannot open a handle to the process.");
    }

    h_snap = CreateToolhelp32Snapshot(TH32CS_SNAPTHREAD, 0);
    if (h_snap == INVALID_HANDLE_VALUE)
    {
        CloseHandle(h_process);
        error("fatal error", "Cannot create toolhelp snapshot.");
    }

    Thread32First(h_snap, &te32);

    while (Thread32Next(h_snap, &te32))
    {
        if (te32.th32OwnerProcessID == proc_id)
        {
            break;
        }
    }

    CloseHandle(h_snap);

    allocated_memory = VirtualAllocEx(h_process, NULL, 4096, MEM_COMMIT | MEM_RESERVE, PAGE_EXECUTE_READWRITE);
    if (!allocated_memory)
    {
        CloseHandle(h_process);
        error("fatal error", "Cannot Allocate Memory.");
    }

    h_thread = OpenThread(THREAD_ALL_ACCESS, FALSE, te32.th32ThreadID);
    if (!h_thread)
    {
        VirtualFreeEx(h_process, allocated_memory, NULL, MEM_RELEASE);
        CloseHandle(h_process);
        error("fatal error", "cannot open a handle to the main thread");
    }

    SuspendThread(h_thread);
    GetThreadContext(h_thread, &ctx);

    buffer = VirtualAlloc(NULL, 65536, MEM_COMMIT | MEM_RESERVE, PAGE_READWRITE);
    ptr = (LPBYTE)buffer;

    memcpy(buffer, shell_code, sizeof(shell_code));

    while (1)
    {
        if (*ptr == 0xb8 && *(PDWORD)(ptr + 1) == 0xCCCCCCCC)
        {
            *(PDWORD)(ptr + 1) = (DWORD)LoadLibraryA;
        }
        if (*ptr == 0x68 && *(PDWORD)(ptr + 1) == 0xCCCCCCCC)
        {
            *(PDWORD)(ptr + 1) = ctx.Rip;
        }

        if (*ptr == 0xC3)
        {
            ptr++;
            break;
        }

        ptr++;
    }

    strcpy((char*)ptr, dll_path);

    if (!WriteProcessMemory(h_process, allocated_memory, buffer, sizeof(shell_code) + strlen((char*)ptr), nullptr))
    {
        VirtualFreeEx(h_process, allocated_memory, NULL, MEM_RELEASE);
        ResumeThread(h_thread);

        CloseHandle(h_thread);
        CloseHandle(h_process);

        VirtualFree(buffer, NULL, MEM_RELEASE);
        error("fatal error", "Failed to write process memory.");
    }

    ctx.Rip = (DWORD)allocated_memory;

    if (!SetThreadContext(h_thread, &ctx))
    {
        VirtualFreeEx(h_process, allocated_memory, NULL, MEM_RELEASE);
        ResumeThread(h_thread);

        CloseHandle(h_thread);
        CloseHandle(h_process);

        VirtualFree(buffer, NULL, MEM_RELEASE);
        error("fatal error", "Failed to set thread context.");
    }

    ResumeThread(h_thread);

    CloseHandle(h_thread);
    CloseHandle(h_process);

    VirtualFree(buffer, NULL, MEM_RELEASE);

    MessageBox(NULL, "SUCCESS", "injected", NULL);

    return NULL;
}

I tried to research and a lot of stuff but still haven’t fixed my code crashing the target process.