Ads not showing on android device, but shows test ads on emulator

Question

So i have this app on the market right now, and it doesn't show the ads. I found it weird so I started to debug. The ads worked fine on the emulator and it said something like "You are running a test ad" on the ad banner.

However now that im trying to debug with an actual android device i see that no ad really shows up. I tried everything, all the questions simillar to this etc. But nothing has helped yet.

Currently just trying to see even test ads on my actual device isn't working and giving me this error:

There was a problem getting an ad response. ErrorCode: 0
Failed to load ad: 0

Here is my code:

MainActivity onCreate:

MobileAds.initialize(this, "ca-app-pub-api key stuff");
mAdView = (AdView) findViewById(R.id.adView);
adRequest = new AdRequest.Builder()
          .addTestDevice("74555080... device test id stuff")
          .build();
mAdView.loadAd(adRequest);

XML for adview:

 <com.google.android.gms.ads.AdView
            android:id="@+id/adView"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_alignParentBottom="true"
            android:layout_centerHorizontal="true"
            android:layout_marginBottom="5dp"
            ads:adSize="BANNER" />

And android manifest:

<uses-permission android:name="android.permission.INTERNET" />

I have created my ad banner almost 3 weeks ago, I am aware it takes a while, but 3 weeks is not a while, there must be a problem that I am not seeing.

If anyone know how to contact Google about this, or a fix please let me know because this is really frustrating as to why my ad unit isn't showing up.

My ad unit by the way is just a basic banner i made, 0 mediation groups, 0 campaigns with it (i don't know if that matters.)