Safari will not login to plusnet webmail

[#1]

I normally use Windows Live Mail 2011 for all my own and my wife's emails (using ISP PlusNet) and my default browser is IE 11.  To assist my wife, my son arranged for her emails to also appear on an iPad.  Recently I wanted to check on one of my wife's emails that had "disappeared" from the iPad so I logged on to PlusNet using the iPad default bowser Safari, and tried to login to PlusNet webmail.  However Safai kept displaying a message "Login failed" with no other explanation as why it had failed.  The same thing occurred when I used Safari on my desktop PC, but using IE and exactly the same login details I was able to see the relevant emails
Since the login works with IE but not with Safari I suspect there is some "incompatibility" between Safari and PlusNet.  Please can anybody explain why this is happening or what I may be doing wrong?

[#2]

I've seen this before with other webmail providers, always on iOS devices.
When you switch to the password field, double check that Safari hasn't set the keyboard to uppercase for the first character.

[#3]

Many thanks for your reply avatastic.  This might be a possibility with the vitrual iPad keyboard, although I have noticed in various sites this doesn't happen when in the password field.  However when I am working from my PC and using the 'real' hardware keyboard I would need to press the Caps key to input an upper case character, and I am certain I did not do so.

[#4]

I've just logged in to PN webmail in Safari on both OS X and iOS without issue.

[#5]

Hi Chaldon,
Do you get the same problem in Safari using the 'basic webmail' option?