Live Editor not shown?

Hej everyone,

i just got a second domain (http://www.studivt-ipu.de/) – theme is twenty seventeen (updated), installed wordpress and the page builder. Everything works fine, but there is no “live editor” button shown – not in the editor at the backend nor at the bar on the frontend.

I had an other domain before, same theme, lots of plugins, older WP-version. Everything worked fine. After wordpress-update the live-editor was shown on the frontend-bar, but no longer on backend. I deleted this domain (no longer needed). Things i’d tried with the new one:

– disable all no-siteorigin-plugins
– other theme (twenty sixteen)
– downgraded wordpress
– downgraded PHP
– cleared browser cache ( i didnt use any other plugin jet, just played around with the costumer)
– I tried another Frontend-Editor (motopress content editor) and it worked with an older wordpress version, but i need and want to continue with siteorigin.

Any ideas? I am not a pro with .php and stuff like that, the only thing i can do is google it and follow step by step instructions^^
Thank you very much.
Ju