If you get a message similar to, "Could not create SSL/TLS secure channel."... please install a newer version of the .NET Framework from Microsoft. Vista can only use v4.6. Others should install the newest available, like v4.8.
I have been looking around and cannot seem to find a way to have ACT run for both FFXIV and EQ2. I haven't played too much with the settings as I use ACT mainly for raids on FFXIV and would rather not break it:)