There are a couple of things to look at and check off the list.
1. The pedals or crank nuts/ bolts could be loose and need to be tightened.
2. A belt could be misaligned or has been knocked slightly off its track.
3. Something internally could be loose and need to be tightened.
Best thing to do is take a video of the noise and try to describe in detail where/ when the clicking noise happens to the best of your knowledge. Our support email, firstname.lastname@example.org is the best channel of communication and we will be happy to get the issue resolved!