Difficulty using stan for phylogenetic comparative methods

Modeling
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1

Hello, I am just starting with stan, and was hoping to use it for phylogenetic comparative methods. I was following a tutorial which I found to try to learn how to do this ( Estimating Phylogenetic Multilevel Models with brms) , and using the sample data of the tutorial it worked fine. So I decided to try to run it on my own data, as follows:

A <- ape::vcv.phylo(SSBTreeEdge)

model_global <- brm(
  OSSB ~ Sexual_Dichromatism_Score + 
    Sexual_Size_Dimorphism_Percent_Imputed + Sexua_Dichroamtism_Binary_Imputed + 
    Female_Song_Present + devo_mode + breedsys_known + median_clutch_size + 
    Pop_Density_Log + (1|gr(SSBTreeEdge, cov = A)),
  data = SSBDensityImputed,
  family = gaussian(),
  data2 = list(A = A),
  chains = 4, iter = 500000, thin = 5000,
  prior = c(
    prior(normal(0, 10), "b"),
    prior(normal(0, 25), "Intercept"),
    prior(student_t(3, 0, 20), "sd"),
    prior(student_t(3, 0, 20), "sigma")
  )
)
)

Where SSBTreeEdge is the phylo object with branch lengths of the species which I am interested in my analysis. However, when I did this, I got the following error:

Error: The following variables can neither be found in 'data' nor in 'data2':
'SSBTreeEdge'

I tried two ways to get SSBTreeEdge into data2, one was to mate SSBTreeEdge = A, and the other to make A = SSBTreeEdge. The latter got me the error:

Error in UseMethod("isSymmetric") : 
  no applicable method for 'isSymmetric' applied to an object of class "phylo"

and the former got me the error of

Error: Object 'A' was not found in 'data2'.```

How do I resolve this issue so that I can include the phylogeny in the covariance matrix

2

Where the vignette has (1|gr(phylo, cov = A)), phylo is a column of the dataframe passed to the data argument of brm, and A is the name of one of the elements of the list passed to the data2 argument (see data2 = list(A = A)).