Hi,
IN XX Network we have observe sudden VoLTE drop and the bucket identify in MME drop,
Finding Possible cause of MME drop reason and outcome to minimize from the NW…
Required your suggestion and finding from your experience
Hi 
,i am not expert but i think the best thing is to determine the scope of the problem (all the network or partial) and do traces to catch the cause ,because there maybe many reasons , the scope helps to determine the reason for example if the whole network most likely from core , if some sites could be radio , traces helps to determine the exact reason
the best thing is to open ticket with the vendor ,they have rules to follow and tools to save the time they may ask for the logs and traces.
The Process is already initiated … Seeking support who had already done… to get early resolution ,
Thanks