we've migrated an existing SiverStripe Website with a customer login to a new server. Since then existing customers can't login to the website anymore. If we register a new member for the website the login is possible.
Any idea or hint how to solve this is very welcome.
Unfortunately I don't know how to get the SilverStripe version. We've inherited the installation of the former agency. I just did a clone without an update and just copied files and restored a mysqldump.
If, in your site root, there is a directory 'sapphire', you're on 2.4 or below. If you have a directory 'framework' you're on 3.0 or above. On versions below 3.0 you should be able to see the version number in the footerbar of the CMS, to the right.
If this is an older site (say 2.3.x), this might have something to do with this ticket: http://open.silverstripe.org/ticket/3004.
[EDIT] Of course I don't know about your site and if this is at all possibl - is it in production already? - but I'd suggest you prevent other users from registering for the time being, until you find out what the cause is. Otherwise you might end up with a mix of password settings...
'Right now the domain is only available if you modify the /etc/host file manually.'
I'm not sure what you mean, and how this connects to the problem at hand? Unfortunately, based on you information alone I don't really know how to tackle this problem.
Do you still have access to the previous hosting and the old version of the website? Or do you know the password for one of the old useraccounts, so you could add a new user with the same password? In that case you could check the hashes (see the MemberPassword table) and see how they are different...