This incident has been resolved.
We have experienced issues with delivering callbacks for some payments during specific timeslots over the past two days.
Wednesday, September 6th:
From 13:28 CEST to 14:33 CEST
Thursday, September 7th:
From 11:37 CEST to 13:24 CEST
If your integration depends on callbacks, please double-check your payments in the Quickpay Manager.