Trying to edit file in vi and it crashes [1]+ Stopped

Found this question, this is what I see: Swap file error message while trying to edit .vimrc file?

But in my case, I can delete swap files, try to edit file and Ctrl-Z and I get this:

[6]+  Stopped                 vi /etc/xinetd.d/tftp
[root@localhost ~]# vi  /etc/xinetd.d/tftp 

[7]+  Stopped                 vi /etc/xinetd.d/tftp
[root@localhost ~]# 

So, for some reason something doesn't let me save this config file. I'm new to Linux and use vi for all config files (and this one as well) but I see this first time. Just won't save - keep giving [x]+ Stopped errors.