[Xperia/SailfishX] New SIM card not working in Xperia

I ordered a new sim card (from Simplytel which is a reseller and uses Telefonica as far as I know). The new card works perfect in my Jolla 1 but is not recognized in the new Xperia. I am not asked for the pin and it always says that no network is available. I tried a different sim card (from FONIC, a Telefonica reseller as well) and that worked worked with the Xperia.