A lot of the MAG boxes won't play 4K or HEVC files - MAG 250, 254, 256, 322, 349 - not that there is much 4K live content, but there are 4K films.
Informir the company that produces the MAGs and built their company on the hardware and software for IPTV services have the ability to block boxes & force software updates which can also cause problems (even if software updates settings are off).
There are other solutions available - for those suggesting Amazon Firestick - thats a long way from the best solution, a cheap option - for a reason. Both for IPTV & Satellite, for those wanting international content. Better hardware available.
For local Spanish content - as mentioned above an antenna for terrestrial is free and Canal+ is the Spanish version of UK Sky - just don't expect everything in multiple languages.
Paul
http://www.televisiontechnology.eu