If you are receiving a activation lock when you insert your Tesix Sim, this means yours device has a iCloud Lock on it. You will need to log into your iCloud to remove this lock.
If you forgot it, follow the instruction on your screen to reset password. If you purchased the device from someone else you will need to connect with them to get the iCloud log in.
Check for Activation Lock before you buy a device from someone else
Before you buy an iPhone, iPad, or iPod touch, from someone other than Apple or an authorized Apple reseller, make sure that the device is erased and no longer linked to the previous owner’s account.
- Turn on the device and slide to unlock.
- If the passcode lock screen or the Home screen appears, the device hasn't been erased. Ask the seller to completely erase the device by going to Settings > General > Reset > Erase All Content and Settings. Don't take ownership of any used iPhone, iPad, or iPod touch until it's been erased.
- Begin the device setup process.
- If you're asked for the previous owner’s Apple ID and password, the device is still linked to their account. Hand the device back to the seller and ask them to enter their password. If the previous owner isn't present, they can remove the device from their account by signing in to icloud.com/find. Don't take ownership of any used iPhone, iPad, or iPod touch until it has been removed from the previous owner’s account.
You will know that a device is ready for you to use when you're asked to "Set up your iPhone," “Set up your iPad," the first time you turn it on.
If you buy a device that's still linked to a previous owner's account, contact them as soon as possible and ask them to erase the device and remove it from their account.
If you can not do any of the steps above the next recommendation will be to contact Apple's customer service and have them removed the activation Locke. In order for apple to do this, you will need to show proof of purchase.