It's unusual but maybe the solar enviroment have been altered and the gate isn't functional for a day, as part of the dynamic universe, as the Custodian way gate. Check the news at a bar as the Planet Malta near to see if this is the reason.
Also, it seems that if you can't dock a gate from a side, and you enter formation with a char(somebody else) who can pass by the gate, it works for him but not for you(even while in formation).