I've the following code:

library(SIAMCAT)
library(phyloseq)
library(microbiome)

# Load my data
load("~/Data/PSM.RData")

# Same taxaonomic rank
pseq_genus <- phyloseq::tax_glom(psm, taxrank = "Genus")

# Log10 normalization
feat <- abundances(pseq_genus)
feat <- log10(feat + 1)

# My MetaData
meta <- pseq_genus@sam_data
meta <- data.frame(meta[,c("Sex", "AgeYrs", "Site", "Smoking", "BioProject", "size_MB")])
label.meta <- - create.label(meta=meta,
                             label="Sex", case="female") 

The error:

Label used as case:
   female
Label used as control:
   male
+ finished create.label.from.metadata in 0.001 s
Error in -create.label(meta = meta, label = "Sex", case = "female") : 
  invalid argument to unary operator

Here my datasets summary:

 > str(feat)
     num [1:134, 1:148] 3.37 0 0 2.22 0 ...
     - attr(*, "dimnames")=List of 2
      ..$ : chr [1:134] "OTU_001_Genus_Streptococcus" "OTU_002_Genus_Porphyromonas" "OTU_003_Genus_Prevotella_7" "OTU_004_Genus_Fusobacterium" ...
      ..$ : chr [1:148] "ERR494388" "ERR494389" "ERR494391" "ERR494392" ...
 > str(meta)
    'data.frame':   148 obs. of  6 variables:
     $ Sex       : Factor w/ 2 levels "female","male": 1 1 1 1 1 1 1 1 1 1 ...
     $ AgeYrs    : int  41 41 56 56 19 19 44 44 46 46 ...
     $ Site      : chr  "Subgingival" "Plaque" "Subgingival" "Plaque" ...
     $ Smoking   : chr  NA NA NA NA ...
     $ BioProject: chr  "PRJEB6047" "PRJEB6047" "PRJEB6047" "PRJEB6047" ...
     $ size_MB   : chr  "7" "19" "18" "9" ...

sessionInfo()

R version 4.1.0 (2021-05-18)
Platform: x86_64-apple-darwin17.0 (64-bit)
Running under: macOS Mojave 10.14.6

Matrix products: default
BLAS:   /System/Library/Frameworks/Accelerate.framework/Versions/A/Frameworks/vecLib.framework/Versions/A/libBLAS.dylib
LAPACK: /Library/Frameworks/R.framework/Versions/4.1/Resources/lib/libRlapack.dylib

locale:
[1] it_IT.UTF-8/it_IT.UTF-8/it_IT.UTF-8/C/it_IT.UTF-8/it_IT.UTF-8

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

other attached packages:
[1] microbiome_1.14.0 ggplot2_3.3.5     SIAMCAT_1.99.3    phyloseq_1.36.0   mlr3_0.13.3      

loaded via a namespace (and not attached):
  [1] nlme_3.1-157           matrixStats_0.61.0     bitops_1.0-7           progress_1.2.2         RColorBrewer_1.1-2    
  [6] bbotk_0.5.2            PRROC_1.3.1            GenomeInfoDb_1.28.4    numDeriv_2016.8-1.1    mlr3learners_0.5.2    
 [11] tools_4.1.0            backports_1.4.1        utf8_1.2.2             R6_2.5.1               vegan_2.5-7           
 [16] DBI_1.1.2              BiocGenerics_0.38.0    mgcv_1.8-39            colorspace_2.0-3       permute_0.9-7         
 [21] rhdf5filters_1.4.0     ade4_1.7-18            withr_2.5.0            mlr3misc_0.10.0        prettyunits_1.1.1     
 [26] tidyselect_1.1.2       gridExtra_2.3          compiler_4.1.0         glmnet_4.1-3           cli_3.2.0             
 [31] Biobase_2.52.0         lgr_0.4.3              scales_1.1.1           checkmate_2.0.0        palmerpenguins_0.1.0  
 [36] mlr3tuning_0.12.1      stringr_1.4.0          digest_0.6.29          minqa_1.2.4            paradox_0.8.0         
 [41] XVector_0.32.0         pkgconfig_2.0.3        parallelly_1.30.0      lme4_1.1-28            rlang_1.0.2           
 [46] rstudioapi_0.13        shape_1.4.6            generics_0.1.2         jsonlite_1.8.0         dplyr_1.0.8           
 [51] RCurl_1.98-1.6         magrittr_2.0.2         GenomeInfoDbData_1.2.6 biomformat_1.20.0      Matrix_1.4-1          
 [56] Rcpp_1.0.8.3           munsell_0.5.0          S4Vectors_0.30.2       Rhdf5lib_1.14.2        fansi_1.0.3           
 [61] ape_5.6-2              lifecycle_1.0.1        infotheo_1.2.0         pROC_1.18.0            stringi_1.7.6         
 [66] MASS_7.3-56            zlibbioc_1.38.0        Rtsne_0.15             rhdf5_2.36.0           plyr_1.8.7            
 [71] grid_4.1.0             LiblineaR_2.10-12      parallel_4.1.0         listenv_0.8.0          crayon_1.5.1          
 [76] lattice_0.20-45        Biostrings_2.60.2      splines_4.1.0          multtest_2.48.0        hms_1.1.1             
 [81] beanplot_1.2           pillar_1.7.0           igraph_1.2.11          uuid_1.0-4             boot_1.3-28           
 [86] reshape2_1.4.4         codetools_0.2-18       stats4_4.1.0           glue_1.6.2             data.table_1.14.2     
 [91] nloptr_2.0.0           vctrs_0.3.8            foreach_1.5.2          tidyr_1.2.0            gtable_0.3.0          
 [96] purrr_0.3.4            future_1.24.0          assertthat_0.2.1       gridBase_0.4-7         survival_3.3-1        
[101] tibble_3.1.6           lmerTest_3.1-3         iterators_1.0.14       IRanges_2.26.0         cluster_2.1.2         
[106] corrplot_0.92          globals_0.14.0         ellipsis_0.3.2