Error: chol(): decomposition failed when running XMAP function

[luckycns]

Hello,

I encountered an error while running the XMAP function in R. The error message is chol(): decomposition failed. Below is the code snippet that caused the issue:
xmap <- XMAP(simplify2array(list(R_YY, R_LL)),
cbind(z_YY, z_LL),
n = c(median(sumstat_YY_i$n), median(sumstat_LL_i$n)),
K = 10,
Omega = OmegaHat,
Sig_E = c(c1, c2),
tol = 1e-6,
maxIter = 200,
estimate_residual_variance = FALSE,
estimate_prior_variance = TRUE,
estimate_background_variance = FALSE)
Could you please advise on how to resolve this issue?

Thank you!