WhatsApp got blocked in Iran but stopped working for Iranians traveling abroad

There are multiple reports that after the Iranian government blocked WhatsApp in Iran, WhatsApp stopped working even for Iranians living outside of Iran who still have WhatsApp on their Iranian phone number with the +98 country code:

https://twitter.com/nima/status/1572706514841878529

So far Meta has not been forthcoming on what is the reason behind this. This was the Meta's non-response to the question: https://twitter.com/WhatsApp/status/1572955312478625792

"The core of our mission is to connect people privately. We are not intentionally disrupting access to our platform, nor are we blocking Iranian numbers. We do everything in our technical power to maintain our services and enable the use of all users in the world."