Error : "Account: Account est obligatoire." while creating ticket

[Romuald RIVET]

Users can't create ticket,

[Nic Brough -Adaptavist-]

You have a field called "account", which is flagged as mandatory for this project and issue type.  So when you create an issue, you need to fill it in.  But I'd guess you have removed it fro the create screen, so users cannot do that.

Either make the field optional in the field configuration, or add it back to the issue creation screen.