I had this problem - it arises on Redhat 8 because you have specified a hostname of something for your machine -
Eg I assigned the name irongate to my machine -
This means I get the prompt something like
irongate root@irongate>
Normally your machine is assigned localhost.localdomain as its name, it is complaining about the fact you have not specified the hostname or a domain name correctly, Redhat seem to favor their visual xtools over the host file so it is a pain to change it all around! - the easiest way is to log into xwindows and go to redhat icon->server settings->network (or something similar) this will bring up a gui for network administration - search the tabs to locate the one where it asks you for host entries - it should read something like:
127.0.0.1 localhost.localdomain localhost 'your defined hostname'
If it reads anything else edit the entries until your other hostname is as defined above - then go to the last tab and in the hostname section type:
localhost.localdomain
Now your computer belives it is called localhost it has an alias of whatever you specified and the loopback address 127.0.0.1 is intact - whew! Now reboot your machine and you should find no errors....
Apache is reporting a different problem - apache is trying to use your defined hostname as the FQDN for your webserver - it wants an address like
www.mybloodycomp.com and all your giving it is mybloodycomp ! I am not sure how to rectify this one - I have been told it is in the httpd.conf file you can specify what Apache should use - assign it something like mybloodycomp.lan this way you are unlikely to get any errors on your LAN - if you are going to create a public web server the address you specify must be your domain name and you reroute the A records of your domain name to point to your server so people can find it!!
Hope this helps - its a bit vague in places because I havent opened up this can of worms since I put it to bed...