我使用 RStudio，昨天我将 R 更新为以下版本：
R version 4.0.0 (2020-04-24) -- "Arbor Day"
Copyright (C) 2020 The R Foundation for Statistical Computing
Platform: x86_64-w64-mingw32/x64 (64-bit)
现在，我无法连接到任何 CRAN 镜像（我已经尝试了 4 个不同的镜像）或安装软件包。当我启动 RStudio 时，我在启动时收到以下错误：
Error in tools::startDynamicHelp() : internet routines cannot be loaded
Warning: namespace ‘lme4’ is not available and has been replaced
by .GlobalEnv when processing object ‘lmer1’
Warning: namespace ‘ggplot2’ is not available and has been replaced
by .GlobalEnv when processing object ‘plot1’
Warning: namespace ‘emmeans’ is not available and has been …