#Trending: Saudis rejoice as WhatsApp Calling works - temporarily

Saudi Arabians celebrated on Friday, albeit briefly, when WhatApp's free calling service "miraculously" began to work despite a months-long nationwide ban.

Saudis quickly took to Twitter to spread the good news using the Arabic-language hashtag #WhatsAppCallsAllowed, for a few hours while a technical error permitted them to call their friends without cost.

Last June, Saudi Arabia's telecoms regulator blocked WhatsApp's free calls to protect service providers' competitiveness in the local market.

"Rejoice, be merry and have fun! Although I think the money we're going to save from phone calls, we'll end up paying in increased data prices," tweeted Hajar Hawsawi.

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Abo Basil al-Ghamd joked: "The current state of the nation: 'Hello. Yeah. Can you hear me well? No'. As everyone is sitting in the same room."

A hopeful Wedad Mansoor thanked King Salman, the crown prince, and the deputy crown price for the free calls.

Alas, the fun and games soon came to an end.

Twitter users then shared images of the app telling users: "Phone call cannot be made. The mobile phone service provider does not support WhatsApp calls."

WhatsApp Calling lets users make domestic and international phone calls for free, using their mobile phones' internet connection rather their cellular plans' voice minutes.

Conventional international calls and texts are a lucrative earner for telecom operators in Saudi Arabia, which hosts around ten million expatriates. The rise of foreign workers using mobile phone apps to communicate with relatives abroad reportedly led to last year's ban.