"Authentication required" in VM Frontend pages

[extonjaez]

Hello,

I'm already logged in my site in frontend like SuperUser (in an article page by exemple).
but when i open a VM page, a popup with "Authentication required" is displayed (see picture attached)
(in a smartphone only (Chrome IOS, Firefox IOS, Chrome Android)), no popup issue in desktop)
i can close the popup without difficulty to navigate in the page.
But how to remove this popup displayed ?
Many thanks for your help
Arnaud

System Information
VirtueMart 3.2.12
PHP Built On    Linux info 3.0 #1337 SMP Tue Jan 01 00:00:00 CEST 2000 all GNU/Linux
Database Version    5.5.58-0+deb7u1-log
Database Collation    latin1_general_ci
Database Connection Collation    utf8mb4_general_ci
PHP Version    7.1.12
Web Server    Apache
WebServer to PHP Interface    cgi-fcgi
Joomla! Version    Joomla! 3.8.3 Stable [ Amani ] 12-December-2017 15:00 GMT
Joomla! Platform Version    Joomla Platform 13.1.0 Stable [ Curiosity ] 24-Apr-2013 00:00 GMT
User Agent    Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:57.0) Gecko/20100101 Firefox/57.0

[Jörgen]

No top domain ? .com, .org etc ?

regards

Jörgen @ Kreativ Fotografi

[extonjaez]

No top domain ? .com, .org etc ?
regards
Jörgen @ Kreativ Fotografi

https://www.arena.cards/creation
but the problem happens only when you're logged..

[Jörgen]

This gives 403 error:

http://www.arena.cards/creation

What is you domain name ?

regards

Jörgen @ Kreativ Fotografi

[Studio 42]

Problème étrange, un soucis de plugin system peut être ?

[extonjaez]

This gives 403 error:
Jörgen @ Kreativ Fotografi

Now error 403  protection was removed for your country, you can retry.
Many thanks for your help

[Studio 42]

Do you have check the cookie domain setting in Joomla ?

[extonjaez]

Do you have check the cookie domain setting in Joomla ?

Do you want to explain please..
It s about the cookie Authentication - Cookie ? (see attached picture)
Thanks for your help?
Arnaud

[Studio 42]

No, the Joomla config > cookie domain.