Ikea Stolmen connection post slipped in

Hello everyone,
I have a request for all the experts here.
With the cabinet system "Stolmen" the inner tube slipped into the large connecting posts. Now I can't get it out anymore. Is there a trick to get it out again? I would find it strange if there is no way, because that can happen very easily and quickly.
I look forward to any tip!
Thanks in advance!

Push out again from the other side with a broomstick or similar...