TCM - Alert: Failed to Save Document through Content Handler

Receiving the following error when attempting to upload/save an attachment in TCM:
Failed to save document through content handler. Unable to contact server to save document.
or
The following file(s) contained unsupported characters (%, [ ). Please correct the filename and re-import.

• EERP
• Munis
• Content Manager
• TCM
• HTML Web Viewer 

Filename could contain a special character causing TCM to not render/save the document successfully. 

Please try clearing browser cache. If this is not successful, please try below steps:

1. Verify the filename of the file being uploaded to TCM does not contain any special characters such as %,#,@,*, [ etc. 
2. If filename does contains special characters, rename the file and test again.
3. If filename does not contain special characters and/or renaming the file is not successful to uploading, please contact CM Support for further assistance.