Error trying to install PHP client on Debian 9

When I enter this command:

sudo dpkg -i couchbase-release-1.0-4-amd64.deb

I get the following error:

dpkg: error processing archive couchbase-release-1.0-4-amd64.deb (–install):
subprocess new pre-installation script returned error exit status 1
Errors were encountered while processing:

Not sure what to do, as the error message is totally unhelpful…
Thanks in advance.

You can follow the guide on archives page and add this source to your APT

deb stretch stretch/main

It worked. Thank you!
(guide is here: