System.Runtime.InteropServices.COMException: 'There was no match for the specified key in the index. (0x80070491)'

Question

Hi Team,

Am trying to add permissions on an excel file from .net core 6. Am using Microsoft.Interop.Excel and Microsoft.Office.Core libraries. On debugging i got to know the error is in line

workbook.Permission.Add('******@domain.com',MsoPermission.msoPermissionRead, new DateTime(2025, 12, 31))

Note: Same code is working for few machines but for few its giving this error.

can anyone help me to get an idea, what can be the probable issues. I have checked for few possibilities but didn't got anything concrete:

• Checked for Office Version : Same for both machines
• Checked for .Net version : Same for both machines
• Checked for Access Level : Used admin access in machines having issue

Can you provide some pointers what else can be the reason?