I have the same exact problem. I can login if I keep hitting the Log In button repeatedly until the stated time is up; waiting won't do it, I tried that. I have also tried a completely fresh install of the viewer, a new viewer, clearing my cache, restarting my computer, logging into different sims, and had another person paying me.
By the way, it happens no matter what viewer I am using, so that's not it. And to make matters more frustrating, it's only this account; none of my alt accounts have a problem. I thought I fixed it yesterday when I turned off HTTP Get Textures, but it only worked once. Damn frustrating to have to keep pressing the log in button repeatedly, but I guess it's the only way,... unless someone can help. I'll submit a help ticket too, like that will help, lol.
TIA,
Lira