Cannot attach documents to email in iCloud
I am suddenly unable to attach a document to my iCloud email. Started about 2 to 3 weeks ago and it is not all documents. Seems to be some Word docs and some Adobe PDFs, each from different folders on my hard drive. I have several PDFs that I need to share with others and have to go to a different email account (non-iCloud) to attach and send them. What is the problem?? And more importantly, how can I fix and/or avoid this? Thanks to all who can help.
Windows, Windows 6