Go to Menu > Settings > Wireless and network > Mobile networks > APNs (may also be called Access Point Names) If you see any APN created, delete it so that there is no problem.
To delete them, enter each one of them and press the secondary button on your phone and click Delete
When they are all removed, follow the steps in this manual
First of all, if you have a profile installed, you have to delete it by going to Settings> General> Profiles> And delete the existing profile
Download this Plugin (by clicking we click on “Allow”) You have to download it with the Safari browser
Once downloaded, we enter Settings> General> Profiles and click on the downloaded profile and click on “Install”