We use ManageWP to manage 100+ client sites. Duo Security v2.2 plugin works perfectly with ManageWP white-listed IP addresses. However, when we updated to Duo v2.3 plugin our ManageWP admin cannot login to our sites.
When we reinstall v2.2 everything is working again; so it appears just to be an issue between v2.3 and ManageWP IP addresses. *interestingly, our network IPs work fine on both v2.2 & v2.3 ... and we really need ManageWP IPs to work with Duo Security. We prefer Duo over all other 2 form factor services; but we simply can't do without ManageWP