0xc0000005 access violation executing location 0x7DAD768FF when DoModal function is called in VC++

UINT XyzApp::DlgThread(void* pThis)
{
       XyzDlg* pDlg = new XyzDlg(*(XyzApp*)pThis);
       ((XyzApp*)pThis) -> m_pDlg = pDlg;
       pDlg -> DoModal()
       ...
}

This is a Visual C++ project developed in Visual Studio 2017. Initially it was developed in Visual Studio 2015, but later i ported it to VS2017 and was working fine.

There was code which was used to send a data from this project to a hardware device. I wanted to use this same code in a different page. So i copy-pasted it to the other page. When i tried executing i am getting the error mentioned below.

I am getting the error at the line when the DoModal() function is being called saying "Unhandled exception at 0x7DAD68FF in Xyz.exe : 0xC0000005: Access Violation executing location 0x7DAD68FF"

If more information is required to debug this problem, please let me know, since this is a big project i have mentioned the problem statement in a concise manner.