I'm a developer myself so I'm hoping that there will be enough information for you to create a Jira task with this report.
I'm a super-host and last night a guest was not able check-in and some others had a similar problem in the past. Finally I worked out what the issue was. Within the check-in documents, which gets sent to the guests like 48 hours before check-in, I have a Google Docs link:-
https://docs.google.com/document/d/12z6OlTLCuZT_jhK04ky1XmmwiYojm_B17v8f2Axxx/
This is straight forward enough.
IMAGE URL : www. hodfords. com / images / mobile_view.jpg
So what happened was that the guest copied the link from the AirBnb app and then pasted onto his browser but the wrapping in the URL caused an extra %20 to be added to the URL which caused an error.
IMAGE URL : www. hodfords. com / images / url_truncated.jpg
Perhaps you can add a URL parser in the Check-in Documents so that users can click on any URLs rather than having to copy and paste URLs which could cause problems such as these.
So, the guest was not able to check-in yesterday because of this.