Unfortunately, Google recently announced that they took the extension down from the store temporarily because of issues with the "Use of Permissions and User Data Privacy."
The following message was posted to the Dashlane status page:
"Currently, our Extension cannot be downloaded from the Chrome Web Store. This issue has no impact on users that already have our Chrome extension installed and running. Only users needing to download our Chrome extension for a first time install or a reinstall will encounter the issue. We are working actively with Google to have it back as soon as possible. Thank you for your patience and understanding."
This is just a small part of a saga that's been unfolding since January 10th, when one of Dashlane's senior engineers received a warning that the extension's use of permissions was not in alignment with Google's terms of service and that the company had seven days to correct the issue.
The engineer responded right away explaining why the extension used permissions the way it did, and in response, Google pulled Dashlane from the store.
In any case, as the Dashlane announcement indicated, if you already have the extension installed, you can certainly continue using it as you have been. However, if you need to reinstall it for any reason, you'll need to wait until it reappears in the Google Chrome Web store before you can do that.
It's a very good, well-respected extension, so it's unlikely that it will remain out of the Web Store for very long, and it will be interesting to find out why Google pulled it so abruptly after the company sent an explanation in response to the warning.