Lost connection with NodeRED

My project use the NodeRED plugin to count the number of messages sent to the server , and it was working as expected for more than a month (The last value in the output bucket should be about 660). A few days ago I fount that my server lost connection with the NodeRED plugin on 22nd July, and the counter stopped counting since then (my edge device and the data bucket was working, but the counter just stop counting as can be seen in the following figure). I redeployed the same flow on NodeRED without making any changes 2 days ago, and it worked again.
May I ask if there were any updates on the server on 22nd July that disconnected my data bucket from the NodeRED plugin and is there any way to prevent this happens again?