vBulletin issue with members login in

I'm not sure if anyone here would be able to help fix the problem I'm having on my forum as no one can work out why.

Since upgrading to the newest version 4.1.2 when people try to log in using internet explorer they have issues signing in.

It won't let people sign in.

When you type our name and password you get the following message.

You have entered an invalid username or password. Please enter the correct details and try again. Don't forget that the password is case sensitive. Forgotten your password? Click here!

You have used 1 out of 5 login attempts. After all 5 have been used, you will be unable to login for 15 minutes.

This is happening to everyone who is using internet explorer.

The other problem when signing in when you type the password, instead of the password staying hidden when you type it with the little black dots, it shows you the actual wording of your password.

Every other web browser seems fine.

It only happens with internet explorer.

Can someone please help me solve this problem as we are starting to lose members.

It did it with our previous version which was 4.0.3

Was hoping the new VB would have fixed it but it didn't.

I'm not the licence holder of the forum so I can't get help from Vbulletin them selves.

Frustrating as hell.

Someone save me

 

come on anyone can help?

 

This thread has no true solution but I would first check if adding/removing www. from the address makes a difference in logging in with IE.

Code:

ie. try to login to http://site-name.com
and then to         http://www.site-name.com

see if there is a difference.  
If there is a difference then some sort of redirect might work.

 

no difference with both