java.lang.IllegalStateException: No thread-bound request found: Are you referring to request attributes outside of an actual web request, or processing a request outside of the originally receiving thread? If you are actually operating within a web request and still receive this message, your code is probably running outside of DispatcherServlet/DispatcherPortlet: In this case, use RequestContextListener or RequestContextFilter to expose the current request.

List oArgs = [];
Map oModel = ['messages': []];
oArgs = [oAtendimento_ti.id, oAtendimento_ti, oAtendimento_ti.solicitacao, oAtendimento_ti.solucao, oAtendimento_ti.atendente, oAtendimento_ti.fechamento];
oModel.messages = [Aplicacao.internacionalize("email.atendimento.ti", sMensagem, oArgs)];

protected static def g;
	/**
	 * internacionaliza uma mensagem usando o i18n
	 * 
	 * @param _sCode REQUIRED - The code to resolve the message for. Used for custom application messages.
	 * @param _sDefault (optional) - The default message to output if the error or code cannot be found in messages.properties.
	 * @param _args (optional) - A list of argument values to apply to the message when code is used.
	 * @return a Mensagem internacionalizada
	 */
	public static String internacionalize(String _sCode, String _sDefault, List _args) {
		g = g?: grails.util.Holders.applicationContext.getBean( 'org.codehaus.groovy.grails.plugins.web.taglib.ApplicationTagLib' );
		return g.message(code: _sCode, default: _sDefault, args: _args);
	}