"Check network connection and try again" won't stop showing!

[AC Question]

A couple of days ago my phone started to show a message saying "Check network connection and try again". I have read multiple threads but this exact message keeps on showing. I have unistalled snapchat, outlook and viber, but none of these seems to be the problem. I'll try to upload a screenshot of the message although I'm not sure how to do it XD. I'm using Galaxy S7 edge.

 

[angel uzunov]

I just created an account so I could upload the screenshot. The message show everytime I turn off Mobile Data or WIFI. ������

 

[Soharang]

I downloaded all the apks in my device and tried binary search, finally I found this annoying toast popup comes from Pinterest app.
I just deleted it and there's no more problem now.

 

[john doe112]

I downloaded all the apks in my device and tried binary search, finally I found this annoying toast popup comes from Pinterest app.
I just deleted it and there's no more problem now.

You are a hero and a saint. Pinterest was the exact cause of this for me.