You will not get any useful help in any forum because your post does not give any coherent information about your actual problem.
You mention several things, but what is actually the problem?
- you can't login?
- you can't register?
- the wiki can't send mails?
So please stop jumping from one thing to another and describe
- what is your current setup (eg. what does work already. is the wiki accessible via the network already?)
- what is the actual problem (what did you expect, what happens instead)
- what have you tried to analyze the problem and what have you learned (any log messages that might be helpful?)
And please remember "doesn't work" is not a helpful error description.
So please try again.