This error is triggered by translating the page. If you disable the translation from your browser window, you should be able to submit without issue.
Chrome
If you use Chrome, click on the translation icon at the right of the address bar:
Alternatively, you can access the translation options from the menu at the right corner of the window:
Safari
If you use Safari, you can also find the translation icon at the right of the address bar:
Firefox
If you use Firefox, you can also find the translation icon at the right of the address bar:
