The glitch affected thousands of customers’ mobile phone service, mobile data and fixed landline networks, an official source of the operator confirmed to Dinheiro Vivo.

Scores of customers took to social networks to complain about the malfunctioning network equipment.

According to an official Nos source there was “a problem with the 4G network which impacted on some services, namely intermittence in voice and data services”.

The issue arose late Sunday afternoon, and was fully regularised, according to Nos, by around 10.30pm.