Hmmm.... I don't know what's wrong since I have only started collecting Plumerias since April of this year. But I do want to say I'm sorry to hear that and I hope some of the experts here will reply and we can both learn from them. This will be my first winter so I want to make sure I'm doing the right thing.

I hope yours will wake up soon and grow some leaves.

It's a problem beneath the soil. It's either the roots, or there is stem rot below. You should uproot it and examine carefully. Prune away any unhealthy looking roots...they may have just dried up. Repot in a fresh mix and water with some superthrive. If there is any stem rot, you need to cut to clean healthy tissue and root it again.

Have you watered it since bringing it out??

Good luck,
Tony

Tony's right: it should be unpotted and the roots examined. Even in your northern latitude it should be leafed out by now.

If it's still just dormant unpotting, washing off all the dirt and having a good look at the roots won't hurt it at all. It's possible that the roots are still cold and dormant, in which case it should wake after a couple of weeks of the root ball warming up outside.

One poster here lives in Utah and keeps his under lights in his basement all winter, and gets blooms during that time. Not ideal, but if this plumeria is okay you may consider keeping it in a warmer part of the house over winter to shorten the dormancy period. Otherwise your plant is waking too late in the season to ever bloom.

Good luck!

I did take the plant out and cut off some rotted roots. Then repotted it in fresh soil. Then I discover tan scales all over the stem or trunk. What is that and is it lethel. Never noticed it before.

It's hard to tell without a picture, but I wouldn't be concerned.

I took a picture but cant seem to load it. As soon as I click on "preview message" the photo file disappears.
They are hard on the stem and I cant remove them.