Can you find out which HTML tag is not filtered here? Use the XSS cheat sheet on the portswigger labs page or the list on this page + The burp suite Intruder.
You can win a free course if you solve this fast enough! <3 The course is CLAIMED
HTML tag:

a
a2
abbr
acronym
address
applet
area
article
aside
audio
audio2
b
base
basefont
bdi
bdo
bgsound
big
blink
blockquot
e body
br
button
canvas
caption
center
cite
code
col
colgroup
command
content
custom tags
data
datalist
dd
del
details
dfn
dialog
dir
div
dl
dt
element
em
embed
fieldset
figcaption
figure
font
footer
form
frame
frameset
h1
head
header
hgroup
hr
html
i
iframe
iframe2
image
image2
image3
img
img2
input