Starting very precisely on January 6th, we started to see a number of previously reliable domains turn up with secondary MX records that look like these:
cluster1a.us.messagelabs.com cluster1a.eu.messagelabs.com cluster1a.uk.messagelabs.com The domains with these secondary records have primary mx records that look like these: cluster1.us.messagelabs.com cluster1.eu.messagelabs.com cluster1.uk.messagelabs.com Starting on January 6th, successful deliveries to these domains declined about 50%, but did not drop to zero. Engagement at these domains has remained steady. However we are now seeing *tons *of *421 Service Temporarily Unavailable *responses from the secondary MX records while still seeing successful deliveries to the primary MX record. Curious to hear if anyone else is seeing something similar or if anyone can help me understand what might be going on with these cluster1a* MX records. Here are a few example domains: funaisoken.co.jp cimb.com stockland.com.au travelex.com Would love to hear any thoughts or insights. Cheers, Luke
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