I'm calling functions with Rscript from an AWS terminal, and I encountered an error when a function uses mclapply(). The function runs fine in RStudio (AWS AMI) when using the same environment, its just from the terminal with Rscript myFunction.R --json=config.json that an error occurs.

mclapply(1:dim(this.split)[1], SomeFun, mc.preschedule=TRUE)

mclapply quits with the error

all scheduled cores encountered errors in user code

Anyone have an idea if a there is some required parameter when calling from the terminal?

Here is my R environment (printed from inside the function)

R version 3.5.1 (2018-07-02)
Platform: x86_64-conda_cos6-linux-gnu (64-bit)
Running under: Amazon Linux 2

Matrix products: default
BLAS/LAPACK: /anaconda3/envs/r35p27/lib/R/lib/libRblas.so

locale:
 [1] LC_CTYPE=en_US.UTF-8       LC_NUMERIC=C
 [3] LC_TIME=en_US.UTF-8        LC_COLLATE=en_US.UTF-8
 [5] LC_MONETARY=en_US.UTF-8    LC_MESSAGES=en_US.UTF-8
 [7] LC_PAPER=en_US.UTF-8       LC_NAME=C
 [9] LC_ADDRESS=C               LC_TELEPHONE=C
[11] LC_MEASUREMENT=en_US.UTF-8 LC_IDENTIFICATION=C

attached base packages:
[1] stats4    parallel  stats     graphics  grDevices utils     datasets
[8] methods   base

other attached packages:
 [1] rlist_0.4.6.1               stringi_1.4.3
 [3] stringr_1.3.1               seqinr_3.4-5
 [5] rBLAST_0.99.2               ShortRead_1.40.0
 [7] GenomicAlignments_1.18.1    SummarizedExperiment_1.12.0
 [9] DelayedArray_0.8.0          matrixStats_0.54.0
[11] Biobase_2.42.0              Rsamtools_1.34.0
[13] GenomicRanges_1.34.0        GenomeInfoDb_1.18.1
[15] Biostrings_2.50.2           XVector_0.22.0
[17] IRanges_2.16.0              S4Vectors_0.20.1
[19] BiocParallel_1.16.6         BiocGenerics_0.28.0
[21] aws.s3_0.3.12               jsonlite_1.5
[23] configr_0.3.3               optparse_1.6.2

loaded via a namespace (and not attached):
 [1] Rcpp_1.0.1             RColorBrewer_1.1-2     compiler_3.5.1
 [4] base64enc_0.1-3        bitops_1.0-6           tools_3.5.1
 [7] zlibbioc_1.28.0        digest_0.6.20          lattice_0.20-35
[10] Matrix_1.2-14          yaml_2.2.0             GenomeInfoDbData_1.2.1
[13] hwriter_1.3.2          httr_1.3.1             xml2_1.2.0
[16] ade4_1.7-13            grid_3.5.1             getopt_1.20.2
[19] data.table_1.12.2      glue_1.3.1             R6_2.2.2
[22] latticeExtra_0.6-28    magrittr_1.5           MASS_7.3-51.4
[25] aws.signature_0.5.0    ini_0.3.1              RCurl_1.95-4.12
[28] RcppTOML_0.1.6