Hello!
Checkbox id is: file_rejected_33561
Is there a way to click on a checkbox using the part of the checkbox id “file_rejected” ?
Get the XPath for the checkbox. If it has an ID, then the XPath should be trivially just the ID, I think this:
//*[@id=‘file_rejected’]
And that can be used in any of the web form actions.
Unfortunately, it doesn’t work
Peter's XPath didn't work because "file_rejected" is just part of the id.
Try this in an Execute a JavaScript in Browser actions (KM Wiki)
cbElem = document.querySelector('input[id^="file_rejected"]';
cbElem.click();
The ^= means "starts with".
Thank you for suggestion, but your variant doesn’t work 
In that case, you will need to post the URL or the HTML code around the checkbox you want to check, in order for us to be more helpful.