MacOS – Mount Error when attempting to mount a network server

I've been attempting to mount a network server on my computer. I can do it through Finder, but this is inconvenient since I can only connect with one username at a time. I read that mounting via Terminal would allow me to connect with multiple usernames at the same time. I found this post: How can I mount an SMB share from the command line? where the command to mount is

mount_smbfs //user@SERVER/folder ./mntpoint

but whether I do that or mount -t smbfs instead of mount_smbfs I get the same error:

mount_smbfs: mount error: [mountpoint path]: Input/output error

Someone even mentioned getting the same error in that post I linked to above, but no one answered him.

Edit:
For the sake of being complete, here's my actual input and output (with the username and password replaced). I even created a new directory /Volumes/testShare to test it with.

Jamess-MacBook-Pro:Volumes magavendon$ mount -t smbfs //[user]:[password]@172.25.206.80 /Volumes/testShare
mount_smbfs: mount error: /Volumes/testShare: Input/output error

And the mount_smbfs command:

Jamess-MacBook-Pro:Volumes magavendon$ mount_smbfs //[user]:[password]@172.25.206.80 /Volumes/testShare
mount_smbfs: mount error: /Volumes/testShare: Input/output error