Link to discount doesn’t work

Hello,
in the last weeks, I saw this message in several of my installation with burst:
https://app.screencast.com/MnvZkKbHdeps6
But every time I click on the Link, I got a 404: https://burst-statistics.com/thanks-for-using-burst/?utm_campaign=burst-free-3.6.0.1&utm_source=tasks&utm_content=trial_offer_loyal_users
Where do I get informations about this offer?
Thanks
Gerd

P.S.: Tried to sent this by https://burst-statistics.com/feedback/, but submit the message doesn’t work in FireFox, Chrome and Edge ;-(

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