Where is the error-log for an GL-AR300M

To possibly find out why I cannot login to the openvpn server, could anyone please let me know how / where to see the log details? In the control panel only a small excerpt is visible.

What are the login credentials to Luci? Have tried all possible combinations og user/root/admin and password/1234/admin/" " to no avail.

Try root/goodlife

FWIW, when I built my OpenVpn Server I used this post to modify some luci pages to add a tab for the logs. Works great

https://forum.openwrt.org/viewtopic.php?id=58715
Modified Status page with 2 tabs for OpenVPN TAP and OpenVPN TUN logs per Post
/usr/lib/lua/luci/controller/admin/status.lua - manages the enu for the gui
/usr/lib/lua/luci/view/admin_status/openvpnlog.htm - adds the content for the OpenVPN Tab.

I put my logs with the system and kernal logs and not under VPN like the author.

The log of openvpn will be in system log, you can get this in Luci or after you ssh to the router, use “logread”

The username of luci is “root”, password is the password you set for the UI for the first time.