Look at these points:
is admin accessible?
are you getting the login page at all?
is mod_security on on this server?
give more details!
[SOLVED] Can't log in after changing hosts
Re: Can't log in after changing hosts
ReneH 
A search will save you hours waiting for an answer!

A search will save you hours waiting for an answer!

Re: Can't log in after changing hosts
Notice : you should put [solved] in the title of your first post in the thread.
Have fun with CMSms
Pierre
Have fun with CMSms
Pierre