Following message is from the Betfair forum.
Please be aware that there is planned maintenance for Tuesday 26th January:
All Betfair.com sites and services (including Poker) will be unavailable between 17:00 GMT and 17:15 GMT for essential maintenance.
Poker customers should be aware that Sit n Go tournaments will be stopped a number of hours in advance of the planned maintenance. These will then enabled again as soon as the Poker product is returned to service.
We would like to apologise for any inconvenience this may cause and assure you that we will do our best to complete this upgrade as soon as we can.