Since last weekend, Movistar and O2 customers, including myself, have been having problems accessing services such as WiFi calls or RCS messages.
In my case, living in an area with poor mobile coverage, this is a serious impediment to making normal voice calls.
As explained by the portal Broadband reason for the failure was the expiration of the domain rhyme-tde.net. This domain identifies the old RIMA (Advanced Multiservice IP Network) transport network is still used for historical reasons in many services.
In the case of WiFi calls, the problem is that the domain of the ePDG server used to connect to the kernel did not resolve. A whois query showed the status of the rima-tde.net domain to be ClientHoldwhich blocks its resolution due to non-payment.
During yesterday the domain was renewed, so customers are regaining access to WiFi calling and RCS messaging.
