The mode was already the way the button points. The Dashboard had been open for a while, and in the meantime the mode was switched in another tab, by another administrator, or by the clock at its Switch off at time. Each button only ever goes its own way, so Disable never switches the mode back on and Enable never takes your page down. The status on the Dashboard is the current one.

Disable pressed after the Switch off at time had passed changes nothing only while WordPress's scheduled switch-off is still to run and the press asked you nothing: that switch-off tells your list shortly. When the press asked you about the launch email, it switches the mode off there and then and emails the list only if you said yes. When nothing was scheduled for that time, it switches the mode off and says how many people were not emailed.

If the message says the screen was open from before an update, the Dashboard was drawn by the version of the plugin before the update, and its button did not say which way it meant. Nothing was changed. Check the status and press the button again.

If the message says your list or site changed after the screen was drawn, the question you answered named a number of people, and somebody has signed up since. Nothing was changed or sent, so your answer is never taken for people it did not name. The Subscribers screen's Send buttons do the same. Reload the screen, read the new number and press again.

I pressed Enable or Disable and it says nothing was changed