Sorry for delayed answer.
You need to go from main menu to “My OSMC” (if you don`t have it, you need to go to “Programs” where you will have it). Picture no. 1.
Open the App store, the shopping basket icon. Picture no2.
Select and click on “SSH server”. Picture no 3.
From left lower corner select “uninstall”. Picture no. 4.
You will see in top right corner some activity and when its finished will show a message that its successfully uninstalled. Restart the RPi and do again the steps from above but you will have to select on step 4 from lower left cornet “install”. Let rpi to install and after the message with succesfully install restart rpi. Try now to access through SSH. 