The most common reason for this issue is that the file size of the Word document may be too large for the email server to handle. Try reducing the file size by compressing images or using a file sharing service instead.
First, try downloading the attachment and opening it directly on your computer. If it still does not open, the document may be corrupted. You can try restoring an earlier version of the document or using a file repair tool to fix it.
This could be due to the email client converting the document to a different format. To avoid this, you can convert the Word document to a PDF before attaching it, as this format is less likely to have formatting issues.
Check if the recipient has the correct software (Microsoft Word) to open the document. If they do, try sending the document in a different format, such as a PDF. If they still cannot open it, there may be an issue with their email client or internet connection.
To prevent attachments from getting lost, always double-check that the attachment is included before sending the email. If your attachments are getting blocked by the recipient's email server, try sending them in a compressed format or using a file sharing service instead.