If you want delegates or certain groups to be able to login by a certain time, please use the following setting options:
You can remove the tick from "is active" (at the bottom) in the participant administration. The account remains, but the login is not allowed at that moment. There will then be an error when trying to log in. If necessary, this should be pointed out explicitly so that no irritations arise.
When time X is reached, check the box again and allow access to OpenSlides.
Hints and tips
Accounts can also be set to active/inactive via the multiselect (> Participants > 3-point menu > Multiselect > Make selection) in the 3-point menu via "Switch account on/off".