Yes, I've been having the same issues. I had a regular S6 before which worked perfectly until the end of it's life. After buying the S8, I am all of a sudden having many issues with staying connected to the network. I get a message that states "Server Response Error, Try Again Later", as seen in my own thread here: S8 "Server Response Error, Try Again Later"
I have restarted the phone, kept the phone off for an extended period of time, changed my sim card, called customer service (which was absolutely no help at all, as all they had me do was change my WiFi calling settings. Before changing at his instruction, these settings were identical to how they were before on my S6. He was also very condescending towards me and treated me as if I didn't know what I was doing or how to properly set up my phone, which I do). This has been very frustrating as I am still in the same work and home locations as before where I was getting close to perfect signal and data access.
Needless to say, it's been very hard knowing that every single day I'm not connected to WiFi I have a problem simply loading even the Play Store and other apps.