Any updates here? I think I may have a similar problem here.
We did eventually set up a test using a read-only domain controller. It’s been a long time since then, but I recall that I wasn’t able to reproduce the issue. In email discussions with pietropau and his associates, we determined that this was likely a DNS issue at the branch office where the openHistorian system was unable to locate the RODC on the network. We didn’t get a definitive response back from pietropau about whether they were able to resolve the issue, but I’d like to think that no news is good news.
If you are merely having trouble logging into the openHistorian Manager and/or the web interface, there is a good chance your issue is completely unrelated to the RODC problem described here. I recommend starting your own topic and providing more details about your specific situation.