Form: clients can't advance to the next page

We've had a couple clients report that they can't advance to page 2 of a form.  It works for all of us internally, and I tried it on my phone, which works.  Just wondering if you have some troubleshooting tips we can give our clients when they have this problem?  I think it must be user error, but I can't figure out what they might be doing to cause this.

I checked your form but can't seem to find any condition in the first page that would not let them move to the next page.

We could suggest to your users to give out the steps they did, so that we can replicate the error and find a solution.

Let us know if the issue still remains,so that we can check it out further.