Backups fail because there was no connection to the repository "Error 2712" (75983)

Error 2712-can't create directory cifs was occurring on all backups and can’t mount a repository to ESX Host.
ESX (not ESXi).

Backups fail because there was no connection to the repository.

Test connectivity to the repository:

1) Using Putty (or other SSH client) connect into your ESX host.

2) Upgrade your login privileges to root by typing su – and enter root password.

3) Create a directory by typing mkdir /mnt/test and then hitting enter.

4) Map this directory to the repository share by using the appropriate command below.

mount -t cifs //<repository name or IP>/<share> /mnt/test -o user=<useraccount>

If the mount command fails with a “mount-12” error:

1. Check the Event Viewer -> System Log on the Repository server. Look for a red X, and the word Error. The Source is Srv. The error will be:

The server's configuration parameter "irpstacksize" is too small for the server to use a local device. Please increase the value of this parameter.

2. Edit the following registry key and increase the DWORD Value (default is 15 in decimal). Recommend increasing it to 18

HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\LanmanServer\Parameters\IRPStackSize

3. Reboot the computer