# Interpolation of non-rectangular data failed

I want to interpolate a type of data which is on a triangular lattice in order to make DensityPlot faster(ListDensityPlot is so slow). However, the interoplation failed with error, no matter setting InterpolationOrder->1 or InterpolationOrder->All

Here is a less dense data

data = Import["https://pastebin.com/raw/6XmFDzmf"];
plotData =
Partition[
StringCases[data, x : NumberString :> InternalStringToDouble@x],
3];
Interpolation[plotData]


it will raise several errors

Interpolation::udeg: Interpolation on unstructured grids is currently only supported for InterpolationOrder->1 or InterpolationOrder->All. Order will be reduced to 1.

Interpolation::femimq: The element mesh has insufficient quality of 0.. A quality estimate below 0. may be caused by a wrong ordering of element incidents or self-intersecting elements.

Interpolation::fememtlq: The quality 0.of the underlying mesh is too low. The quality needs to be larger than 0..

What does it mean? How to interpolate such data or general non-rectangular data?

PS: the density plot is

epsilon = 10^-7;