So, I have set up a double verification to access my yahho email, apart from typying in password I need to type in an access code I get from yahoo. These numbers from yahoo are random and consist a code.
I am not using yahoo email on my phone, just use it on my laptop.
So, I expected to receive a message with an access code and instead of that I got one sms with chinese letters and immediately the second one from one of my contacts with the proper access code which worked alliwing me to access my yahoo email.
I contacted a person I reiceved an access code from but she was as suprised as me.
I immediately did a hard reset of the phone and now I receive the strange empty messages I described above.