There are two reasons that you might be seeing the message 'Invalid SIM'.
Your device is locked to another telco
The most common reason for the message 'Invalid SIM' is that your phone, tablet or hotspot is locked to another telco network e.g. Telstra. If you bought your device from another telco they'll often lock your device so that it's not as easy for you to move to another telco.
If you bought your phone or tablet from another telco and you're seeing the message 'Invalid SIM' all you need to do is contact the company that you bought it from and ask them to unlock it. It's really easy for them to do this and it shouldn't take much longer than a phone call with them and turning your device on and off.
Until you've unlocked your device there really isn't too much we can do to resolve this one, so annoying as it might be, please give your old telco a call and make sure your phone is unlocked and if you're still having trouble please get in touch.
You've been unlucky and been sent a faulty SIM card
If your device is definitely unlocked and working fine and you're still having problems you could have a faulty SIM - unfortunately this does happen from time to time.
So if you've got a good reason to think your OVO SIM card is faulty give us a bell on 135 686 and we'll be happy to help. Our team are online to help you with this kind of thing:
Monday – Friday: 9:00am – 8:00pm (AEST)
Saturday – Sunday: 10:00am – 6:00pm (AEST)