First of all I have to say I am not an expert. I searched the forum and found the following text. After reading this carefully, this turned out to be the solution for me.
It turned out that, due to my impatience, I had skipped some steps. 
Best Regards,
Frans
link: Added Bitwarden Free in my Chrome Extensions, but keeps "saying" Vault is closed - #4 by Ruud
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