When trying to purchase the Premium Season Pass, it may happen that this gets stuck and it cannot be completed.
The most frequent cause is the presence of an active ad blocker in your browser.
Relaunch the game on a different browser or in incognito mode.
If this doesn't fix the issue, try again later (or the next day at the latest).
Before you report this: Check the login page for updates on widespread problems. Any global issue affecting gameplay will be posted there. Visit the support portal for announcements, which are typically shared in English.