download failed notifications keep reappearing

Yesterday I tried to download a pdf file and the download failed. The usual notification appered in the corner, which I swipped away to remove. Since then it has reappeared countless times, as if the download attempt were somehow stuck on repeat. I am at a loss for how to stop this from happening. I have deleted history and cached data, quit firefox, shutdown and restarted. The download failed notifications just keep reappearing. If anyone can help I would greatly appreciate it. Thank you in advance.