I've been using 1Password for quite a while now. But my Firefox refuses to connect to 1Password Helper. I've found out it has something to do with FoxyProxy, which prevented the Extension from working. After some digging in this forum I came across serveral ports which are used by 1Password to communicate. I cannot change the Proxy Configuration .pac file directly, but I've found a possible solution to make it work, which I like to share with you.
I've created a new proxy configuration in FoxyProxy which I've called "No proxy for 1Password" there I've created a Whitelist rule with following regular expression pattern in the URL-pattern tab:
This configuration has direct connection to Internet seleted in the proxy detail tab. This rule is now on top of my configuration. Now it works like a charm!