ive got a nokia 6230i and it doesnt matter what sim card i put in the phone ive tries every sim on every network but on the screen it just say's insert sim card.
check if the sim card connections are ok and have not been pushed down so they are not touching the sim card,if so then bend them back with a needle or anything small enough!(be very carefull whilst doing this as they could snap off if you over do it! If that fails try giving them a clean with a cotton bud and some meths.
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