Problem with advertising

[tifil24]

Hello,
 
I have a little problem of publicity. Let me explain.
Since last night, when I lock and unlock my phone, an advertising window appears. Only when I turn on to the Internet (either wifi or mobile data), when I have not Internet enabled, this does not occur.
When I click the multitasking button, there is no name in this window, I looked in the current process, I did not see anything strange. Nor even in the installed apps.
I tried various antiviral application to scan the phone, but nothing has been detected.
 
I have no idea what it may come, I installed an application store, but an ultra-known application, so it is not something sensible.
 
What do you advise me to do? (If it's possible, I don't want to do a factory reset ^^).
 
thank you in advance

[_alexdon_]

Can you try to dial *#*#73556673#*#*?

EDIT: @Viridis thanks for saying that, perhaps he should also check safe mode.

[Lord_viridis]

It's more than very likely a ram or battery optimisation app.
Seen many cases like this and each time it was a "optimising" app

[tifil24]

So, I do *#*#73556673#*#*, but then what I do ?

I check If I've always the same problem ?

[_alexdon_]

That's for when the device has demo mode enabled (its basically the word SERVICE). Check if the same occurs after dialing. If it still does, boot in safe mode.

[tifil24]

I did the *#*#73556673#*#*, but it does nothing, I mean when I put the last "*", nothing occur.

Whan I boot in safe mode, I don't have my problem, when I unlock my phone, nothing appear

[_alexdon_]

In this case, it's something you have installed. Apps like CM security apps or similar can cause this.

[tifil24]

I don't have any apps like this installed on my phone.

And, when I see all my apps, I can't say where do it came from.

[_alexdon_]

You can only check one by one. It might have been an website as well. Boot back in normal mode and see if the same occurs.

[tifil24]

After the safe mode, I boot again in normal mode, but I have always the same.

I will try with one by one, I will uninstall one by one and check.