VERIFIED SOLUTION i

Resolve MHWebPortal web application is not responsive in Portrait Dialogue

Issue

Opening an emarketing message template in Message Designer in Portrait Dialogue version 6.1 takes up to three minutes before they open or they may not open at all.
 

Cause

Portrait Dialogue 6.1 works with Microsoft .Net Framework v4.5 and Microsoft .Net Framework v3.5 but not with version 4.6 which was found on the customer's environment and which is not supported version for Portrait Dialogue 6.1.
User-added image

It is supposed that not supported version came with Windows Update for Windows components.
 

Resolution

UPDATED: April 20, 2017
It is necessary to install the correct version of Microsoft .Net Framework.