IndexError: list index out of range

Comfyui is running . After completing the drawing, sometimes may encounter such problems, and at this time, you can only restart the comfyui service;

How should I solve this problem? Thanks！

log:
got prompt
Exception in thread Thread-2 (prompt_worker):
Traceback (most recent call last):
File "/root/miniconda3/lib/python3.10/threading.py", line 1016, in _bootstrap_inner
self.run()
File "/root/miniconda3/lib/python3.10/threading.py", line 953, in run
self._target(*self._args, **self._kwargs)
File "/root/ComfyUI/main.py", line 111, in prompt_worker
e.execute(item[2], prompt_id, item[3], item[4])
File "/root/ComfyUI/execution.py", line 355, in execute
recursive_output_delete_if_changed(prompt, self.old_prompt, self.outputs, x)
File "/root/ComfyUI/execution.py", line 229, in recursive_output_delete_if_changed
input_data_all = get_input_data(inputs, class_def, unique_id, outputs)
File "/root/ComfyUI/execution.py", line 28, in get_input_data
obj = outputs[input_unique_id][output_index]
IndexError: list index out of range

Is it caused by insufficient memory or VRAM？