Due to unusual SMS volume, SMSes sent by some customers were processed with certain delay.
Like any other messaging system, we have queue-based architecture, We need to manage the throughput sent to downstream providers, we can’t process at higher speeds.

Due to high volume and bandwidth limitation, the delay was observed particularly for certain customers who were sending bulk messages.

This problem was observed for the following duration:-

Date : 4th Sept 2019
Start Date Time - 2019-09-04 12:30:00 UTC
End Date Time - 2019-09-04 17:30:03 UTC

Date : 5th Sept 2019
Start Date Time - 2019-09-05 13:30:00 UTC
End Date Time - 2019-09-05 16:30:03 UTC

Mitigation:- We have further optimized our queueing mechanism to avoid this problem.