Confluence Activity Gadget won't authenticate another confluence instance

 com.atlassian.oauth.serviceprovider.ConsumerInformationRenderException: Could not render consumer information
    at com.atlassian.oauth.serviceprovider.internal.servlet.authorize.AuthorizationRendererImpl.render(AuthorizationRendererImpl.java:63)

caused by: com.atlassian.templaterenderer.RenderingException: org.apache.velocity.exception.MethodInvocationException: Invocation of method 'render' in class com.atlassian.oauth.serviceprovider.internal.servlet.authorize.AuthorizationRendererImpl$AuthorizationConsumerRenderer threw exception java.lang.IllegalArgumentException at authorize.vm[line 16, column 35]
    at com.atlassian.templaterenderer.velocity.one.six.internal.VelocityTemplateRendererImpl.render(VelocityTemplateRendererImpl.java:97)

caused by: org.apache.velocity.exception.MethodInvocationException: Invocation of method 'render' in class com.atlassian.oauth.serviceprovider.internal.servlet.authorize.AuthorizationRendererImpl$AuthorizationConsumerRenderer threw exception java.lang.IllegalArgumentException at authorize.vm[line 16, column 35]
    at org.apache.velocity.runtime.parser.node.ASTMethod.handleInvocationException(ASTMethod.java:337)

caused by: java.lang.IllegalArgumentException
    at java.net.URI.create(URI.java:842)

caused by: java.net.URISyntaxException: Illegal character in path at index 144: http://confluence.atlassian.com/rest/gadgets/1.0/g/com.atlassian.streams.confluence:activitystream-gadget/gadgets/conf-activitystream-gadget.xml
    at java.net.URI$Parser.fail(URI.java:2809)