Open Teamviewer with URI start.teamviewer.com

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We start teamviewer via our browsers with the URI: start.teamviewer.com/device..

This worked till MacOS 10.13 but with 10.14 this does not work anymore. What happens now is when we use a URI it always download a new teamviewer, no matter what. But we all have teamviewer on our Macs. 

Can someone tell me what I can do about it?

Thanks !