The invention relates to a method (20) for authenticating to a mobile network. According to the invention, the method comprises the following steps. A device activates (22) only a first temporary subscription identifier. The device sends to a first server the first temporary subscription identifier (24) and first data (212). The first server sends to the device a first result message (216) including an authentication failure based upon the first data. The device activates (220) only a second temporary subscription identifier. The device sends to the first server the second temporary subscription identifier (222) and second data (232). And the first server sends to the device a second result message (236) including an authentication success based upon the associated first and second temporary subscription identifiers and the second data. The invention also relates to corresponding device and system and a server for authenticating devices to a mobile network.