If you ever get the below error while you try to activate screen (Unix Screen Utility) as a different user rather than your login . (for ex: i logged in as john and sudo admin and type screen at prompt).
Cannot open your terminal ‘/dev/pts/7’ – please check
1) Exit out of the user First.
2) cd /dev/pts/7
3) chmod +0666 /dev/pts/7
4) then sudo su user
5) type Screen. then it’ll work.
Please let me know if this doesn’t work..