Common Browser Extension Conflicts
Some web browser extensions can cause interference with other extensions. This document will address extensions that cause conflicts with 1Password specifically.
Firefox Extensions
NoScript
One of the most common conflicts is NoScript. Due to the way NoScript disables Javascript on pages it can prevent 1Password from automatically filling your username and password into login forms. If the webpage is allowed by NoScript then it should fill the data properly again.
Request Policy
Request Policy can prevent the 1Password extension from communicating with the 1Password helper. We've written a guide on how to configure Request Policy.
AdBlock Plus
Non-default installations of AdBlock Plus can prevent the 1Password extension from communicating with the 1Password helper.
For some users, disabling and re-enabling the extension can resolve the conflict.
FoxyProxy
A common problem for users of the FoxyProxy extension is that local traffic is blocked or routed through a proxy. Due to the way the 1Password extension communicates with the 1Password helper, local traffic needs to remain local. If your proxy information is automatically configured by using a pac file you may need to edit the file to allow local traffic. This is something you can ask your network administrator about.