This either happens automatically when an error rate threshold is crossed, or manually by a member of the IFTTT team.
A paused service does not perform trigger checks, so Applets will not run. The Check now button is also disabled.
As soon as the service is unpaused, Applets will continue to work as expected.
Whether or not trigger events that occurred while the service was paused will now be picked up depends on the nature of the underlying issue and the service itself.
Visit the status page to check out which services are currently paused and subscribe for updates.