Why am I getting Mount Error (121), Remote I/O Error?

I followed the instructions on this web page to setup a shared folder on a Windows 7 computer so I could access it on a computer running Ubuntu 16.04.1. http://www.howtogeek.com/176471/how-to-share-files-between-windows-and-linux/

After setting it up, I pasted the mount command into the terminal on the Ubuntu machine and pressed enter. I got the following error. I am a new Ubuntu user and I have no idea what is causing this error. Any help with this will be greatly appreciated!!

howard@howard-AY639AA-ABA-CQ5302F:~$ sudo mount.cifs //fx4130server/linux_share /home/howard/Desktop/Windows-Share -o user=howard
[sudo] password for howard: 
Password for howard@//fx4130server/linux_share:  ******
mount error(121): Remote I/O error
Refer to the mount.cifs(8) manual page (e.g. man mount.cifs)
howard@howard-AY639AA-ABA-CQ5302F:~$

I can connect to the folder on other computers running Windows on my network with no problems.

Solution 1:

Try adding vers=2.1 in your option string:

sudo mount.cifs //fx4130server/linux_share /home/howard/Desktop/Windows-Share -o user=howard,vers=2.1