Problems voting on smartphone

We’ve been running a poll for a few weeks but have today heard feedback from some people that they’ve been unable to register a vote when using a smartphone. Apparently it just ‘hangs’. I know this is a bit vague, and we’re struggling to get meaningful details as to what, where and when this happens, or whether it’s iOS, Android, or both, but have you had any support questions or issues in a similar manner?

For the record, when we heard this I then used my Android phone and could register a vote without a problem. Go figure…