We sometimes have issues with mod_security. Depending on it’s configuration, it can sometimes disrupt our migration process. More info about ModSecurity.
It’s a somewhat rare case but there could be another plugin or your active theme conflicting. Please try to disable all plugins (except WP Migrate DB Pro) on both the local and live sites and attempt the migration again. You should also try activating the default theme that comes bundled with WordPress and attempting the migration. You may also want to enable Compatibility Mode.