Rselenium for rstudio server

Does anybody know how to use Rselenium on rstudio server?

when I run the following:

library(RSelenium)
driver<- rsDriver(browser=c("firefox"))

I get:

checking Selenium Server versions:
BEGIN: PREDOWNLOAD
BEGIN: DOWNLOAD
BEGIN: POSTDOWNLOAD
checking chromedriver versions:
BEGIN: PREDOWNLOAD
BEGIN: DOWNLOAD
BEGIN: POSTDOWNLOAD
checking geckodriver versions:
BEGIN: PREDOWNLOAD
BEGIN: DOWNLOAD
BEGIN: POSTDOWNLOAD
checking phantomjs versions:
BEGIN: PREDOWNLOAD
BEGIN: DOWNLOAD
BEGIN: POSTDOWNLOAD
[1] "Connecting to remote server"

Selenium message:Expected browser binary location, but unable to find binary in default location, no 'moz:firefoxOptions.binary' capability provided, and no binary flag set on the command line
Build info: version: '4.0.0-alpha-2', revision: 'f148142cf8', time: '2019-07-01T21:30:10'
System info: host: 'rstudio.sbg1.pushpushgo.com', ip: '167.114.229.243', os.name: 'Linux', os.arch: 'amd64', os.version: '3.10.0-957.10.1.el7.x86_64', java.version: '1.8.0_201'
Driver info: driver.version: unknown
remote stacktrace: 

Could not open firefox browser.
Client error message:
	 Summary: SessionNotCreatedException
 	 Detail: A new session could not be created.
	 Further Details: run errorDetails method
Check server log for further details.