We're now having issues with emails from 1 of our vendors. The emails arrive, and we see them in our Inbox, and even see the subject and a little text preview of the email. However, when we go to open the email, in the "Advanced Client" the email is blank, but in the "Basic Client" we see the following:

HTTP Status 500 -

type Exception report
message
description The server encountered an internal error () that prevented it from fulfilling this request.
exception
javax.servlet.ServletException: javax.servlet.jsp.el.ELException: An error occurred while evaluating function "zm:getPartHtmlContent"
org.apache.jasper.runtime.PageContextImpl.doHandle PageException(PageContextImpl.java:854)
org.apache.jasper.runtime.PageContextImpl.handlePa geException(PageContextImpl.java:791)
org.apache.jsp.h.imessage._jspService(org.apache.j sp.h.imessage:91)
org.apache.jasper.runtime.HttpJspBase.service(Http JspBase.java:97)
javax.servlet.http.HttpServlet.service(HttpServlet .java:802)
org.apache.jasper.servlet.JspServletWrapper.servic e(JspServletWrapper.java:332)
org.apache.jasper.servlet.JspServlet.serviceJspFil e(JspServlet.java:314)
org.apache.jasper.servlet.JspServlet.service(JspSe rvlet.java:264)
javax.servlet.http.HttpServlet.service(HttpServlet .java:802)
com.zimbra.webClient.filters.CharEncodingFilter.do Filter(CharEncodingFilter.java:45)
com.zimbra.webClient.filters.SetHeaderFilter.doFil ter(SetHeaderFilter.java:322)
root cause
java.lang.NullPointerException
java.util.regex.Matcher.getTextLength(Matcher.java :1140)
java.util.regex.Matcher.reset(Matcher.java:291)
java.util.regex.Matcher.<init>(Matcher.java:211)
java.util.regex.Pattern.matcher(Pattern.java:888)
com.zimbra.cs.taglib.bean.ZMessageBean.getBodyHtml Content(ZMessageBean.java:224)
com.zimbra.cs.taglib.bean.ZMessageBean.getHtmlCont ent(ZMessageBean.java:279)
sun.reflect.NativeMethodAccessorImpl.invoke0(Nativ e Method)
sun.reflect.NativeMethodAccessorImpl.invoke(Native MethodAccessorImpl.java:39)
sun.reflect.DelegatingMethodAccessorImpl.invoke(De legatingMethodAccessorImpl.java:25)
java.lang.reflect.Method.invoke(Method.java:597)
org.apache.commons.el.FunctionInvocation.evaluate( FunctionInvocation.java:172)
org.apache.commons.el.ExpressionEvaluatorImpl.eval uate(ExpressionEvaluatorImpl.java:263)
org.apache.commons.el.ExpressionEvaluatorImpl.eval uate(ExpressionEvaluatorImpl.java:190)
org.apache.jasper.runtime.PageContextImpl.propriet aryEvaluate(PageContextImpl.java:932)
org.apache.jsp.h.imessage._jspService(org.apache.j sp.h.imessage:83)
org.apache.jasper.runtime.HttpJspBase.service(Http JspBase.java:97)
javax.servlet.http.HttpServlet.service(HttpServlet .java:802)
org.apache.jasper.servlet.JspServletWrapper.servic e(JspServletWrapper.java:332)
org.apache.jasper.servlet.JspServlet.serviceJspFil e(JspServlet.java:314)
org.apache.jasper.servlet.JspServlet.service(JspSe rvlet.java:264)
javax.servlet.http.HttpServlet.service(HttpServlet .java:802)
com.zimbra.webClient.filters.CharEncodingFilter.do Filter(CharEncodingFilter.java:45)
com.zimbra.webClient.filters.SetHeaderFilter.doFil ter(SetHeaderFilter.java:322)
We didn't have problems before the ZCS Network Edition upgrade.

If I connect via IMAP using Outlook, the email shows up just fine.

Any assistance is appreciated.