Is TSO down for maintenance?

There is no notice on the homepage and I get this when trying to play:

"We regret that the connection to the "The Settlers Online" server failed. Please try to reconnect. Should the problem persist, please visit the homepage and the forum for more information.

We are working to resolve the problem.

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Your The Settlers Online team"

game is working fine for me

I get redirected to 'https://www.thesettlersonline.com/en/maintenance' after logging in and clicking the Play button.

try clearing browser cache and maybe flush your dns

CTRL+F5 did the trick, cheers Kit :)