Outlook Web App error for new user

Hello,

Recently, our new  user can't get on OWA because their regional setting page is returning "An unexpected error occurred and your request couldn't be handled."

with "Url: https://mail.shdm.org:443/owa/languageselection.aspx" 

I've search many site and i've not been able to find a working solution.

I've check the redirection, everything seems ok

here is the complete detail message

	An unexpected error occurred and your request couldn't be handled.


Request
Url: https://mail.shdm.org:443/owa/languageselection.aspx
User: promoteurs@shdm.org
EX Address: /o=SHDM/ou=Exchange Administrative Group (FYDIBOHF23SPDLT)/cn=Recipients/cn=promoteurs790
SMTP Address: promoteurs@shdm.org
OWA version: 14.3.195.1

Exception
Exception type: System.ArgumentNullException
Exception message: Value cannot be null. Parameter name: value

Call stack
Microsoft.Exchange.Clients.Owa.Core.Utilities.RenderDirectionEnhancedValue(TextWriter output, String value, Boolean isRtl)
Microsoft.Exchange.Clients.Owa.Core.LanguageSelection.RenderTimeZoneSelection()
ASP.languageselection_aspx.__Render__control1(HtmlTextWriter __w, Control parameterContainer)
System.Web.UI.Control.RenderChildrenInternal(HtmlTextWriter writer, ICollection children)
System.Web.UI.Page.Render(HtmlTextWriter writer)
System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)

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Hope that someone can help!
Alexandre