diff --git a/docs.it4i/general/obtaining-login-credentials/obtaining-login-credentials.md b/docs.it4i/general/obtaining-login-credentials/obtaining-login-credentials.md
index ac387e898c70f9b855d182cb53deef2313e88cd3..b8168ecff4353d6527b13892245d58b37e7fa645 100644
--- a/docs.it4i/general/obtaining-login-credentials/obtaining-login-credentials.md
+++ b/docs.it4i/general/obtaining-login-credentials/obtaining-login-credentials.md
@@ -23,7 +23,7 @@ Once authorized by PI, every person (PI or Collaborator) wishing to access the c
 1. Full name and affiliation
 1. Statement that you have read and accepted the [Acceptable use policy document](http://www.it4i.cz/acceptable-use-policy.pdf) (AUP).
 1. Attach the AUP file.
-1. Your preferred username, max 12 characters long. The preferred username must associate your surname and name or be otherwise derived from it. Only alphanumeric sequences, dash and underscore signs are allowed.
+1. Your preferred username, max 12 characters long. The preferred username must associate your surname and name or be otherwise derived from it. Only alphanumeric sequences and dash signs are allowed.
 1. In case you choose [Alternative way to personal certificate](#alternative-way-to-personal-certificate), a **scan of photo ID** (personal ID or passport or driver license) is required
 
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