redis单机部署出现READONLY You can't write against a read only

(error) READONLY You can't write against a read only replica.

以上错误一般只会出现在主从集群配置中，可是我这里是redis单机配置，居然也会出现这样的错误，不太正常。
https://www.cnblogs.com/morgan363/p/13719830.html
按上面的文档，暂且修改一下配置文件
slave-read-only no
再观察一下