Problem with SoE servos AMK and DC

No, I don't have it.
Only free tools - IgH master and SOEM.

And also the EtherCAT Configurator from Beckhoff. But I couldn't spin the engine there. Maybe just for a malfunctioning DC.
Maybe I'll try it again when my servo is spinning elsewhere and now I know that DC is a necessary condition. By the way, it's not written anywhere in the documentation, or at least I didn't find it.

I really don't get it.

In the configuration
<master idx="0" appTimePeriod="1000000" refClockSyncCycles="1000">
it crashes about every 10-15 seconds.

With refClockSyncCycles="-1" it's much worse, it crashes almost every second.

But with refClockSyncCycles="1" it seems to be running reliably. At least for 10 minutes without falling, now.