I had one client who could not connect to a samba share giving the error that the credentials where wrong while I was sure they where not.
This happened suddenly on a laptop with Windows 10 while other clients with Windows 10, Windows 7 and Ubuntu etc. all where able to connect.
At first I was suspecting the problem beeing a change in the hash or key for the share - and maybe it really was because Putty was saying so when I tried to SSH into the server.
But I could not find any saved connection to delete with net use.
The solution was to change a setting in secpol.msc which is accessible as administrator via the search even in Windows 10 Home.
I had to set LAN-Manager-Authenticationlevel to just send NTLMv2.
You will find this setting under Security settings -> local -> Security options -> Network Security: LAN-Manager-Authenticationlevel.
(I translated this from German. Feel free to edit with nativ english wording.)