Workflow stopped due to WorkflowTaskTimeout

Just to add, workflow task has a default 10s timeout. Looking at the WorkflowTaskFailed event properties as Antonio mentioned could help.

I assume that your workflow execution is still running, so yeah you could try to find whats causing the workflow task (an unit of execution of your workflow code, see more info here) to fail and restart your worker(s) to allow it to continue exec on next workflow task retry.