I am comparing different phylogenetic causal models using Phylopath package in R. I managed to get the best fitting model results with their CICs in order, but when extracting the path coefficients of the best fitting model to plot the causal paths, I get the following error:

Error: Fitting the following model: GAP ~ LT80 + SL + TFL80 produced this error: non-finite finite-difference value [1]

I run individually this model using PGLS and it seems fitting fine (no errors). Good to say that some of my variables are highly correlated (LT80 and TFL80), I do not know if that could be the cause.

Could someone help me to solve this error or get the path coefficients in a different way, please? Thank you!