Hi, I tried to upload the following list of usernames:

Opice1956
Rowerin
Melanie anna
Bonifac-cz
Jistefi
Bačkovská
Lidabey
NŠO-ČI
Stana123
Pauza
OmaOla
Antonín Ryska
Libuše Kroková
VETA 7O
Ilča53
Wlady
Markéta z e Lhoty
Klenča
VlaMaul

I extracted this list of usernames from the ListStudents API. Strangely, three usernames are not valid when uploaded to Wikimetrics:

Jistefi	invalid user_name
Pauza	invalid user_name
VlaMaul	invalid user_name

Do you have any idea why these? The order of usernames does not seem to produce any difference, it is always these three.

thanks