How are you running n8n? This is going to either be related to the current cloud issues that we are aware of or you have ran out of disk space on your self hosted install.
At the top of the forum we added a notice about a known issue with Cloud at the moment.
We’re facing some unexpected performance issues on n8n Cloud at the moment, which might lead to slower response times or even timeouts in your workflow. Our technical team is already on it, working hard to fix the situation as quickly as possible. We apologize sincerely for any inconvenience and truly appreciate your patience while we restore our service. We’ll make sure to keep you updated on the progress. Thanks a bunch!
I suspect the issue you are seeing is related to this.