IB a/c logs out and in repeatedly

My IB a/c logs out and But this goes on repetedly within few seconds logs back in. I donot have to enter user name or password or security details. But this goes on repetedly during the day. All other web sites are working properly. I am using internet explorer, and windows 7.

Any body experiencing this sort of problem ? Comments much appreciated. Thanks

 

It is your internet connection.

 

That happened to me pretty regularly when I was using cable modem.

 

My internet connection is fibre optics one from British Telecom. I have tried other web pages and all are working fine,