ASP.NET login works fine locally, fails on remote host

I'm using VS2013 Premium with a complex "single page" web site project.   I'm publishing to file system and uploading with FTP to a remote host.  I'm Just starting to test deployment.

The password based login, using Membership and the built-in Login control, work fine in local development, but fail on the remote host (Arvixe).

The app uses this provider (from web.config, connection string and application name are pseudonyms):

<membership defaultProvider="CustomizedProvider"><providers><add name="CustomizedProvider" type="System.Web.Security.SqlMembershipProvider" 
             connectionStringName="MyConnectionString"
             minRequiredPasswordLength="12" minRequiredNonalphanumericCharacters="1"
             enablePasswordRetrieval="true" enablePasswordReset="true" 
             requiresQuestionAndAnswer="false" passwordFormat="Encrypted" 
             requiresUniqueEmail="false" maxInvalidPasswordAttempts="20" 
             passwordAttemptWindow="10" applicationName="/MyApp" /></providers></membership>

I have verified that the membership application name matches the application name in the aspnet_Applications table.

Any suggestions on what else I can do to diagnose and fix this problem would be appreciated.

Thanks!