Unable to create graph

[hjpotter92]

The systemd service boots up properly, but on visiting the page, it is unable to generate graphs:

Nov 08 01:15:28 hedwig systemd[1]: Started VNStat Web UI.
Nov 08 01:15:28 hedwig vnstatui[989591]: 2019/11/08 01:15:28 starting vnstat-ui 0.8.2 (g6bb9ad7)
Nov 08 01:15:28 hedwig vnstatui[989591]: 2019/11/08 01:15:28 accepting requests on 0.0.0.0:7000
Nov 08 01:15:38 hedwig vnstatui[989591]: 2019/11/08 01:15:38 graph generation error: exit status 1
Nov 08 01:15:38 hedwig vnstatui[989591]: 2019/11/08 01:15:38 graph generation error: exit status 1
Nov 08 01:15:38 hedwig vnstatui[989591]: 2019/11/08 01:15:38 graph generation error: exit status 1
Nov 08 01:15:38 hedwig vnstatui[989591]: 2019/11/08 01:15:38 graph generation error: exit status 1

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[Josh VanderLinden]

@hjpotter92 sorry for the obscene delay in responding to this issue. Did you set the interface(s) that you wish to see graphs for in your /etc/default/vnstatui file? Here is mine, for example:

###############################################################################
# Configuration options for vnstatui:
#
#   -b (string): address to use when listening for requests (default "0.0.0.0")
#   -p (int): port to use when accepting new requests (default 7000)
#   -d (string): data directory for vnstat (default "/var/lib/vnstat")
#   -g (string): comma-separated list of graphs to display (default
#                "summary,hourly,daily,monthly,top")
#   -i (string): comma-separated list of interfaces to display graphs for
#
###############################################################################
OPTS="-i=br0,tailscale0"

The -i flag is what you will want to ensure is set.