SFTPGo does not validate username with special characters

SFTPGo log :

{
  "level":"debug",
  "time":"2024-09-03T07:22:59.841",
  "sender":"connection_failed",
  "client_ip":"10.54.0.1",
  "username":"barnouin-t@univ-nantes.fr",
  "login_type":"password",
  "protocol":"HTTP",
  "error":"Validation error: username \"barnouin-t@univ-nantes.fr\" is not valid, the following characters are allowed: a-zA-Z0-9-_.~"
}

Fouiller dans le code de SFTPGo pour voir ou se trouve la validation des username