Potted climbing plant is dying - any suggestions?

i have a potted Mandevilla plant, which is a climbing flowering vine. i had re-potted it about two months ago, and it was thriving after that. It sits on the deck and gets plenty of sun and it was flowering and doing great. Pot is plenty big for the plant, so all was well. However, we had some period of rain a few weeks ago, and now the soil is very moist and the plant is dying. If it’s not dying, then it sure is not looking too healthy. Flowers are gone and the leaves are brown and droopy.

If it’s dying from too much wet soil, then how do i get it out of that wet soil without killing or ripping the roots?

Or may there be other reasons this plant could be not doing well?

I feel bad for the plant. Help!!