iPhone messenger SSL error and safari error

Hi, few days ago a Messenger (fb app) on my iPhone 6s, out of nowhere, stopped working. Everytime I wanna open the app it asks me about signing in the name and password, after I fill it in appears a problem that you can see in the pic below. I have the latest version of messenger and also of iOS - 11.1.2.

Firstly, I checked the time zone - it's correct, I deleted an app and installed that again, then put my phone into DFU mode, then restarted network settings and location and privacy. Nothing of this worked.

The other problem which looks that could be related is when I try to open facebook.com website on Safari (also on my iPhone) it shows a problem - "Safari cannot ope the page because it could not establish a secure connection to the server."

I'm really lost and I have no clue what else should I do. I'm glad for every answer and I hope that this can be figured out. Thanks.