image not displaying correctly

[Ymarshall]

hello I work with simplecaptcha, on mamachine locally everything works well but I deployed on a tomcat server and the image no longer displays correctly.
there is no error message that could help me better understand the cause
<div class="form-group col-sm-8"> <img src="${createLink(controller: 'captcha', action: 'captcha')}"/> </div> <div class="form-group col-sm-12"> <label for="captcha"><g:message code="captcha.message" /></label> </div> <div class="form-group col-sm-2"> <g:textField name="captcha" id="captchaVal" class="form-control" onblur="verifyCaptcha();"/> </div>

[Ymarshall]

this my application.yml

simpleCaptcha:
fontSize: 30
height: 200
width: 200
length: 6
bottomPadding: 16
lineSpacing: 10
chars: 'ABCDEFGHIJKLMNOPQRSTUVWXYZ'
storeInSession: false