Microsoft Exchange Server is stripping the Aspose Created xlsx files that are attachments from outgoing emails. We are able to send files that are created with Microsoft Excel itself and the files that Aspose has created once RE-SAVED in Excel. And all types of xlsx files… macros ON or OFF … xls / xlsx … and so on … it just boils down to if the file is created by Aspose it will not pass as a valid file and anything created or RE-SAVED (no changes at all to the file just saving again) with MS Excel have no issues.
Thanks for your posting and using Aspose.Cells.
Please download and try the latest version: Aspose.Cells for .NET v22.214.171.124 it should resolve your issue.
I have attached two excel files, one is created with MS-Excel 2013 and the other is created by opening and saving with Aspose.Cells.
Please check if both of them passes or if any of them fails. Then please let us know which of them fails
If your issue still occurs, then please provide us some screenshots highlighting your issue or sample project so that we could investigate this issue further. Thanks for your cooperation in this regard.