Problem with Rcmd.exe when installing packages

I'm getting the following error when installing packages from github:

> devtools::install_github("pmartinezarbizu/pairwiseAdonis/pairwiseAdonis")Downloading GitHub repo pmartinezarbizu/pairwiseAdonis@HEADErro: Failed to install 'pairwiseAdonis' from GitHub:  System command 'Rcmd.exe' failed, exit status: -1, stdout + stderr empty

With find_rtools, I get the following message (I was reading these posts, but couldn't solve my problem: https://github.com/r-lib/devtools/issues/2031 and R CMD check not looking for gcc in Rtools directory):

> find_rtools(T)Scanning R CMD config CC...cc_path:  '' does not existScanning path...ls: C:\Rtools\bin\ls.exe gcc_path: C:\Rtools\mingw_64\bin\gcc.exe VERSION.txtRtools version 3.5.0.4 Version: 3.5 Found compatible gcc on path[1] TRUE

I'm using R v. 3.6.:

>     > session_info()>     - Session info ------------------------------------------------------------------------------------->      setting  value                       >      version  R version 3.6.3 (2020-02-29)>      os       Windows 10 x64              >      system   x86_64, mingw32             >      ui       RStudio                     >      language (EN)                        >      collate  Portuguese_Brazil.1252      >      ctype    Portuguese_Brazil.1252      >      tz       America/Sao_Paulo           >      date     2020-07-29