I have completed the main quest. I have also completed the Arch-mage quests, the main Thieves Guild quests, and the Civil War quests. I am working on a radiant quest for the Thieves Guild. It is a Numbers Job. It requires me to go to Solitude.

However, I can no longer enter the city of Solitude. It tells me I must defend the city. The city has fallen to the Stormcloaks. I saw it all. It finished normally. But, I cannot continue this quest. Please advise.