Unable to launch RStudio Server

[curious.stranger]

Hello everyone,

I hope someone could help me out with an issue that am facing. I have successfully installed R + RStudio Server in an RHEL 7.0+ EC2 machine. Unfortunately, I am unable to access the server. I am not particularly sure what is going on here. Below are some of my findings:

1. Running netstat -lntp shows that RServer is running on the right port.

netstat -lntp
Active Internet connections (only servers)
Proto Recv-Q Send-Q Local Address           Foreign Address         State       PID/Program name
tcp        0      0 127.0.0.1:25            0.0.0.0:*               LISTEN      1169/master
tcp        0      0 0.0.0.0:8787            0.0.0.0:*               LISTEN      27527/rserver

2. Running rstudio-server status shows that the server is active with no issues.

● rstudio-server.service - RStudio Server
   Loaded: loaded (/usr/lib/systemd/system/rstudio-server.service; enabled; vendor preset: disabled)
   Active: active (running) since Mon 2020-09-28 17:58:57 +08; 20h ago
  Process: 27245 ExecStop=/usr/bin/killall -TERM rserver (code=exited, status=0/SUCCESS)
  Process: 27526 ExecStart=/usr/lib/rstudio-server/bin/rserver (code=exited, status=0/SUCCESS)
 Main PID: 27527 (rserver)
   CGroup: /system.slice/rstudio-server.service
           └─27527 /usr/lib/rstudio-server/bin/rserver

Sep 28 17:58:57 PTAWSG-1RPHap01 systemd[1]: Starting RStudio Server...
Sep 28 17:58:57 PTAWSG-1RPHap01 systemd[1]: Started RStudio Server.

3. Running rstudio-server verify-installation yields no results. This seems to be an unexpected behaviour?

4. Looking for the Rserver process ps -aux | grep 'rserver' yields:

rstudio+  1976  0.3  0.0 147480  3456 ?        Ssl  14:29   0:00 /usr/lib/rstudio-server/bin/rserver
root      2010  0.0  0.0 112812   964 pts/0    S+   14:29   0:00 grep --color=auto rserver

5. Hitting URL = http://0.0.0.0:8787/ gets me a Network error : 503 code (tcp_error)

Please advise. Appreciate any help I can get.