Order status does not update after successful payment

Hello, our company recently started to use Mollie Woocomerce plugin. Everything looks great despite one problem. When our customers are making successful payment the order status stays pending. And after a while, it becomes cancelled. The order status should be processing. Where is the problem? How to fix this?

Here are the logs of ordering process:

2018-06-25T14:20:46+00:00 DEBUG mollie_wc_gateway_kbc: Start process_payment for order 32662
2018-06-25T14:20:46+00:00 DEBUG mollie_wc_gateway_kbc: Order 32662 webhookUrl: https://www.persogifts.com/wc-api/mollie_wc_gateway_kbc/?order_id=32662&key=wc_order_5b30d00c32336
2018-06-25T14:20:46+00:00 DEBUG mollie_wc_gateway_kbc: Create payment for order 32662
2018-06-25T14:20:46+00:00 DEBUG mollie_wc_gateway_kbc: Payment tr_Wy9xp6AB7w (live) created for order 32662
2018-06-25T14:20:46+00:00 DEBUG For order 32662 redirect user to payment URL: https://www.kbc.be/olpayment?olpVer=3.0&olpId=S131&langWebSite=E&olpCtx=gkhxEcoMhyA5zPXte6yP2wbrppRnmqu0GGIxeZPQ9SWTB544zYIxY7K8GjBYdVat7Cb157ZQa0m1tDCIHMHW8%2FWI8q4zEGkXmfpKUkR30EQvBXoCx%2BREv2pd8CeN1dIxWBrf7aTvTD5SotITbHbFBjJ2oQJCwJzsFLRxfmE6oxjwKv8LCT1t5bLoxgS3c0npbN53OfSDegnP9cKdhwLhsoVnq3%2FiSDP4iZvxO%2FAcpsBChphGTLATYBPo3Rty9nXum9XqrZYXjDLoDircGQ%2FBz2M5uedYPv5kGXGSSEvWXSqD1nhEI75Sp%2F%2BfwmjB0yFiqAs6zDpF1gCnlwIxwlefyLaSH%2BasGeXv4AgSR7FqR8w%2FVCTf%2BQ%3D%3D
2018-06-25T14:21:16+00:00 DEBUG mollie_wc_gateway_kbc: Order 32662 orderNeedsPayment check: yes, not processed by Mollie gateway.
2018-06-25T14:21:16+00:00 DEBUG Mollie_WC_Plugin::onMollieReturn: Redirect url on return order mollie_wc_gateway_kbc, order 32662: https://www.persogifts.com/checkout/order-received/32662/?key=wc_order_5b30d00c32336&utm_nooverride=1

The page I need help with: [log in to see the link]