This can occur for a number of reasons:
1. You are trying to open it in an incompatible browser i.e. Internet Explorer is not compatible, try Google Chrome, Firefox, Mircosoft Edge or Safari instead.
2. If you are trying to view a PDF file on an iPad it will not open as Apple does not support Adobe PDF.
You will need to change the format of documents that you load to ensure they are not PDFs otherwise you will encounter this again if you rely on using an iPad to access your CRM account. This is something we have no control over.
3. The file is corrupt - check that the original file opens correctly.
4. If you notice that some odd characters have been added to the file name then please remove the file and then rename the file and try uploading again.