Hello there, @Bagya1111.

In QuickBooks Enterprise, the SKU will work if you add a custom field for the SKU numbers. Since you're using a Manufacturer's Part Number (MPN), you can add it to the report instead.

However, if the MPN doesn't exist, let's try running the verify and rebuild troubleshooting.

Here's how:

1. Click the File menu.
2. Go to Utilities, then choose Verify Data. 
3. If QuickBooks detects no problems, there's no further action needed. If you receive a message that says, "Your data has lost integrity," the file is damaged. Just continue to Rebuild Data to correct the problem.
4. When you Rebuild Data, you'll receive a message to back up your company file. Just click OK. The utility starts as soon as the backup is finished.
5. Click OK when you get the message "Rebuild has completed."
6. Run Verify Data again to check for remaining data damage.

After running the utilities, try to check your MPN.

You can keep me updated by tagging me. I will get back to all of you as soon as I can.