Caused by the User
For a variety of reasons, you can decide to switch from online mode to offline mode even if a breakpoint has been set in a section or if you are in step by step mode.
In this case, you must confirm your choice:

Following confirmation, all application tasks are stopped.
Caused by a fault
When a breakpoint is set in a task section, or when you are in step by step mode, if a hardware or communication problem is detected, the PLC switches automatically from online mode to offline mode and the breakpoint is lost without a request for confirmation.