We regularly do updates to the site to improve usability, add features or fix issues.
This means that from time to time you can also have issues with the site.
More often than not, the issue arises from the fact that we may have changed a file on the site and your browser cache is holding on to the old version.
This can also happen if your internet connection interrupted while loading a page and corrupting a file download that is cached.
Before contacting us with the issue, we would suggest you try clearing your browser cache. This will allow your browser to load fresh files from the server.
More info on clearing your cache files: