DrayTek Vigor 2926 router - empty graphs

[eliassal]

I have a fresh new cacti 1.2.19 setup on Fedora 35, mainly to monitor the traffic on my router DrayTek Vigor 2926

FirstI added it as a device with SNMP 2, in the device list it shows it is UP.

In begining, it had some graphs, Cacti-...... but all empty. I did not have any grapgh for traffic and I came across
https://gist.github.com/mitchellrj/fb26bfd976bd039234fd
downloaded the the 2 xml files dropped adslLine.xml into snmp_queries and uploaded cacti_vigor.xml (using the form).

Switched back to the Devices Tab, I saw that graphs number increased and I had several new ones that Start with DrayTek...., the 2 that interests me are

DrayTek - Traffic - 192.168.1.1 (LAN) 65 Data Query In/Out Bytes (64-bit) 200x700
DrayTek - Traffic - 82.65.38.149 (WAN1) 66 Data Query In/Out Bytes (64-bit) 200x700

clicking on any one of them shows empty graph, no measures

I activated debug graph, I get

RRDtool Command:
/usr/bin/rrdtool graph - \
--imgformat=PNG \
--start='-86400' \
--end='-300' \
--pango-markup \
--title='DrayTek - Traffic - 192.168.1.1 (LAN)' \
--vertical-label='bytes per second' \
--slope-mode \
--base=1000 \
--height=200 \
--width=700 \
--rigid \
--alt-autoscale-max \
--lower-limit='0' \
COMMENT:"From 2022-01-12 18\:37\:58 To 2022-01-13 18\:32\:58\c" \
COMMENT:" \n" \
--color BACK#F3F3F3 \
--color CANVAS#FDFDFD \
--color SHADEA#CBCBCB \
--color SHADEB#999999 \
--color FONT#000000 \
--color AXIS#2C4D43 \
--color ARROW#2C4D43 \
--color FRAME#2C4D43 \
--border 1 --font TITLE:11:'Arial' \
--font AXIS:8:'Arial' \
--font LEGEND:8:'Courier' \
--font UNIT:8:'Arial' \
--font WATERMARK:6:'Arial' \
--slope-mode \
--watermark 'Generated by Cacti®' \
DEF:a='/usr/share/cacti/rra/draytek_traffic_in_67.rrd':'traffic_in':MAX \
DEF:b='/usr/share/cacti/rra/draytek_traffic_in_67.rrd':'traffic_in':AVERAGE \
DEF:c='/usr/share/cacti/rra/draytek_traffic_in_67.rrd':'traffic_out':MAX \
DEF:d='/usr/share/cacti/rra/draytek_traffic_in_67.rrd':'traffic_out':AVERAGE \
LINE1:a#00CF00FF: \
AREA:b#00CF007F:'Inbound ' \
GPRINTLAST:'Current\:%8.2lf %s' \
GPRINTAVERAGE:'Average\:%8.2lf %s' \
GPRINTMAX:'Maximum\:%8.2lf %s\n' \
LINE1:c#002A97FF: \
LINE1:d#002A977F:'Outbound' \
GPRINT:d:LAST:'Current\:%8.2lf %s' \
GPRINT:d:AVERAGE:'Average\:%8.2lf %s' \
GPRINT:d:MAX:'Maximum\:%8.2lf %s\n'
RRDtool Command lengths = 1354 charaters.
RRDtool Says:
OK

I visited troubleshooting Tab > Data sources, I found 2 Data sources

DrayTek - Traffic - 192.168.1.1/LAN
DrayTek - Traffic - 88.66.138.149/WAN1

I clicked on both I started to have doted circles round and round since 6 hours and never stop. On Each page, I have the following item with a green check symbol.

Did the poller receive valid data? traffic_in = U
traffic_out = U

As a beginner with Cacti I am not sure which /what I need to do.
Thanks for our help