I tried several times. Net work problem?

Code:

> if (!requireNamespace("BiocManager", quietly = TRUE))
+   install.packages("BiocManager")
> 
> BiocManager::install("org.Hs.eg.db")
Bioconductor version 3.12 (BiocManager 1.30.10), R 4.0.3 (2020-10-10)
Installing package(s) 'org.Hs.eg.db'
installing the source package ‘org.Hs.eg.db’

trying URL 'https://bioconductor.org/packages/3.12/data/annotation/src/contrib/org.Hs.eg.db_3.12.0.tar.gz'
Content type 'application/x-gzip' length 83225518 bytes (79.4 MB)
=========
downloaded 15.1 MB

Error in download.file(url, destfile, method, mode = "wb", ...) : 
  download from 'https://bioconductor.org/packages/3.12/data/annotation/src/contrib/org.Hs.eg.db_3.12.0.tar.gz' failed
Warning in download.packages(pkgs, destdir = tmpd, available = available,  :
  download of package ‘org.Hs.eg.db’ failed

It looks like your download failed (timed out). Please try

options(timeout = 300)
BiocManager::install("org.Hs.eg.db")

Increase '300' further, e.g., to '600', if the download still fails.