404 Dead Link within Jira Plugin and Pretty URLS

Hello! When using an url-pattern like below, I get code 404. When pressing the button the redirected URL looks like it should do. but it is not found

atlassian-plugin.xml

 <servlet name="clientdetails" key="clientdetails" class="jiraplugin.ClientDetails">
        <description>Provides pages for the URL provided.</description>
        <url-pattern>/xx/client*</url-pattern>
    </servlet>

    <routing name="Pretty URL" key="routing" path="/xx/client">
        <route from="/" to="/plugins/servlet/xx/client"/>
        <route from="/{name}" to="/plugins/servlet/xx/client/{name}"/>
    </routing>

and velocity template that directs to client page

<div class="field-group">
	<a href='xx/client/$sponsor.getName()'> 
		<button type="button">Show Client</button>
	</a>
</div>

ClientDetails

@Scanned
public class ClientDetails extends HttpServlet {


	private static final long serialVersionUID = 1L;

	private static final String TEMPLATE = "xx_client_details.vm";

	Map<String, Object> context;

         //some fields
	@Inject
	public ClientDetails (@ComponentImport SearchService searchService, @ComponentImport TemplateRenderer templateRenderer,
			@ComponentImport UserManager userManager, @ComponentImport CustomFieldManager customFieldManager,
			@ComponentImport WorklogManager worklogManager, @ComponentImport IssueLinkManager issueLinkManager,@ComponentImport LoginUriProvider loginUriProvider,
			@ComponentImport PageBuilderService pageBuilderService, BookedHoursTransactions bookedHoursTransactions, @ComponentImport I18nResolver i18nResolver) {
		super();
		//init
	}

	@Override
	public void doGet(HttpServletRequest request, HttpServletResponse response) throws IOException {

		// Include the velocity template
		this.pageBuilderService.assembler().resources().requireContext("xx:xx-resources");

		// Check if the any user is logged in. If not -> login page
		if (userManager.getRemoteUser(request) == null) {
			redirectToLogin(request, response);
			return;
		}

		response.setContentType("text/html;charset=utf-8");

		UserKey currUserKey = userManager.getRemoteUser().getUserKey();
		String currUsername = userManager.getRemoteUser().getUsername();

		// Create default context
		context = Maps.newHashMap();

		response.setContentType("text/html;charset=utf-8");

		context.put("error", "");
		ApplicationUser currUser = ComponentAccessor.getUserManager().getUserByName(currUsername);
		
		
		//some code
		context.put("sponsors", sponsors);

		templateRenderer.render(TEMPLATE, context, response.getWriter());
	}

	private void redirectToLogin(HttpServletRequest request, HttpServletResponse response) throws IOException {
		response.sendRedirect(loginUriProvider.getLoginUri(getUri(request)).toASCIIString());
	}