WhatsApp

https://downdetector.co.uk/status/whatsapp/ 

NOT a Smarty issue - Any issues like this, “Down Detector” should be your first port of call, and yes, WhatsApp has been experiencing issues in the last few days. WhatsApp servers are part of the same server farms as sister services, Facebook and Instagram, who are all owned by parent company, “Meta”

Not scientific by any means, but the weekend just gone was the three day “Memorial Day” weekend in the USA, including yesterday, Monday, so I imagine there has been a lot of traffic through Meta’s servers in the last 72 - 96 hours. 

What do WhatsApp say, Anthony_2620954? 
WhatsApp do have service issues from time-to-time, which can affect how long it takes you to receive chat messages. 

Anthony_2620954 WhatsApp operates via data. Are you using mobile data or wifi?