Having same problem tonight. Trying to log in to Cryodiil tonight and I just sit at the loading screen that shows an artistic rendition of the battle with the small Auryn continuously spinning.
Sometimes this issue, especially when trying to load into Cyrodiil, can be caused by problems with the various graphic elements loading up. Try lowering the graphics before zoning in and see if that helps. After you reach the character select screen, select Options on the left side of the screen. In Graphic Settings, select Minimum and save the settings.
Please let us know if this workaround gets you zoned in.