Unable to add attachments to knowledge base anymore

Unable to add attachments to knowledge base anymore

I have been adding articles to knowledge base in Zoho Desk (as part of Zoho One). Today suddenly i found that I am unable to upload and attachments to the articles. I get the following error:

"Attachment couldn't be added."

I have uploaded the screenshot of the error as well.

Please help in resolving this issue. I have tried uploading different extensions, and it does not work.