The battery icon is gray with a red exclamation sign. Not charging normal. When charging the battery sign doesn't change. When turned off, on the screen appears a big red sign of a battery with an exclamation sign in it. What could it be? How do I repair it?
P.S.: The phone is new.
It likely means that your battery is no longer communicating properly with your phone or is unknown. Usually this is because of dirty battery contacts, some kind of software glitch, or worse, a faulty battery.
You could try the following:
1. Cleaning the battery contacts (on the battery and on the phone itself). That is...if your battery is removable.
2. Do a soft reboot (rebooting the device without resetting any of the options or settings). This is done by holding down some button combination depending your model or if you have a removable battery, by removing the battery for a few seconds.
3. Backup your phone and do a factory reset or hard reset.
If that doesn't work...you are probably looking at a phone or battery replacement. It should be covered by warranty if you still within the warranty period.