Problems registering

Hi all,

We are currently hosting a couple of events. Participants can register for our events using your plug-in which up until this point has worked flawlessly. However a couple of weeks ago we started to receive messages from people that wanted to register for some of our events stating that it was impossible to do so. From the conversations we’ve had with them we’ve gathered that they managed to fill in everything, however when they press send nothing happens. This problem doesn’t occur when personel from the office tries to register these participants. We’re at a loss as to what is the exact cause of the problem. Do you have any suggestions?