Rooted phone but cannot change hosts file I rooted on my S8+. I used the app root checker to check that it's rooted.
I was attempting to block ads by hosts files with this tutorial

I attempted to copy the hosts file to my pc, changed it, and pushed it back... got:

adb: error: failed to copy 'hosts' to '/system/etc/hosts': remote couldn't create file: Read-only file system
hosts: 0 files pushed. 62.2 MB/s (456580 bytes in 0.007s)


I then attempted to do it by following this tutorial which uses apps to change the files

I did change the host file permissions to -rw-rw-rw-

Then I tried to use the editor to add some DNS but I was unable to save the hosts files once again. When I tried to save it, I got a Toast saying root permissions were given to the text editor.

Any ideas?
So I finally was able to come back to this issue.
I was unable to mount the adb with write permissions either because i was not su or it would deny me to change the host files...

I tried to write the text on the hosts file but it was a file with hundreds of lines... even seemed that android was not able to store it in the "copy/paste" 

So in the end I used Solid explorer 2 from play store.

I wrote a hosts file... then i navigate to the /system/etc/ 
and I rename hosts to "hosts.old" and my "hosts.txt" to "hosts"

until now it seems to be working fine

I'm not considering this an answer because I was unable to write on hosts and someone can come up with a better solution