The Inability to Access sites /secure sites (https) e.g. Online banking, Hotmail...etc is usually caused by the followings:

• Incorrect MTU value
• State of SSL on Internet Explorer needs resetting

Incorrect MTU value

Currently in the UK, has only been reported by TalkTalk or AOL customers with regards to incorrect MTU value causing inability to access certain sites or SSL sites. This is due to the fact that TalkTalk or AOL requires a MTU value of 1400 to be set on your router. If an incorrect vale is set then it could cause browsing issues. Please refer to your product manual on how to change your MTU value.

State of SSL on Internet Explorer needs resetting

This usually happens when you change your ADSL modem / router.

To solve this problem

1. Click “Start”
2. Click “Run”
3. Type in “regsvr32 softpub.dll “
4. Click OK. A pop-up should display with the message Dll Register Server in softpub.dll Succeeded.
5. Click OK again.

You can also try the followings:

• Clear cookies and other browser cache. If it is a site you have previously viewed, your browser may get stuck looking through your cached files instead of trying to find the site it needs. 
• Reset web settings. Windows and Internet Explorer can be glitchy; this will reset possible bad settings in the browser.
• Disable any running firewalls. Firewalls can cause some pages to not be viewable, because Firewalls block ports which are vital to view all web pages.
• Uncheck http proxies. Under Internet Explorer > Tools > Internet Options > Advanced, uncheck http 1.1 and http1.1 through proxy connections: This will allow you to view ssl pages and pages that are ssl pages called from a CGI script.
• Restore your OS from the original disks. This is a LAST RESORT, but may be required to fix some problems. Some OS restore disks will not do this.