CMS Made Simple Forums

I upgraded 9 websites from 1.9.4.3 to 1.10
With two of them I now have difficulties to log in.
After entering login name and password on mywebsite/admin/login.php nothing seems to happen, I stay on that login page.
But when I then remove /login.php from the URL (I found that out by accident) I'm suddenly in the backend of the site and everything works fine.
What causes this behaviour? How can I solve it?

Frank

I had the same problem with one of may website.

I fixed it so:
I login without /login.php, go to User Preferences, I changed settings and everything is OK now!

Excuse me for my bad English!

I just found out that for some websites the admin has no troubles, but editors do.
For at least one site all users have this problem.

Thanks Ruil22, That helps me.
Indeed, all accounts that had this problem had this setting:
My Preferences » User Preferences » Homepage: None
Changing that to i.e. Homepage: Content solved this problem.