Error 500 on viewing tax rates in backend

I created a new tax rate and now I get an Error 500 saying this (in a german Google Chrome), when I want to view the tax rate site:

Quote:

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Beim Abrufen von http://***/contao/main.php?do=iso_se...l_iso_tax_rate ist auf der Website ein Fehler aufgetreten. Möglicherweise wird sie gerade gewartet oder ist falsch konfiguriert.

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I just updated to Contao 2.10.4, Isotope is on 1.3.0 rc1 Build 15.

Is this a bug? Can somebody help me?

Hello Michel,

I don't have a solution for your issue. The extension isotope_exceptional might help to solve that issue.

But as you seem to speak German you might want to post this in the German speaking Isotope community.

Jan