I have been getting SIM card errors off and on for some months, but now the situation seems to have stuck. Previously I would just power cycle my phone and it would fix the problem for a while, a week or so. Now, however, my phone will only connect to the network for about 30 seconds before I get a series of errors ultimately leading to “SIM failure” message and “Invalid SIM” as the network status. I’ve tried Apple’s recommendation but to no luck. Any suggestions?