Failed to save a document in Microsoft Word

Hi experts,
Today, I was working over a network and attempted to save a document in Microsoft Word an error message appeared saying “There has been a network or file permission error.
The network connection may be lost. (FileName.doc)”.
What does it mean? Have any idea? A possible solution would be appreciated.
Thanks for assistance.

There has been a network or file permission error.
The network connection may be lost. (FileName.doc)
