Getting DA3001 error message in MPOS

Another way to resolve this is this time very simple: if you are seeing this error in the MPOS UI, and you go to the Event Viewer and there are no events from a Retail Server source, then for sure you have a simpler issue.

Getting Revocation server was offline while working with MPOS

So, I've generated the certificates properly and MPOS worked fine for a period of time, then suddenly it stopped working and been receiving the following message "The revocation function was unable to check revocation because the revocation server was offline.".

Getting User is not authorized when activating MPOS R3 CU9

When installing this particular version from ground up (the Modern POS from a R3 CU9 installation media), you may get this error, unless you have also applied a hotfix for it (not sure at this moment if one exists, but looking into): "Microsoft.Dynamics.Commerce.Runtime.UserAuthorizationException: User is not authorized." and "IsAuthorized threw an exception 'Microsoft.Dynamics.Commerce.Runtime.UserAuthorizationException: Assigned role is not allowed to perform this operation.".

Install Modern appx applications without Windows Store

So, if you are going to install Modern POS on your machine you will need to do an extra step before actually getting to the install part.

The web services for MPOS do not properly respond

In configuring the components for MPOS you might get stuck sometime on the Test Connection step of the Async Client when testing the connectivity to the Async Server. Do not forget the types of each component in the equation here and act accordingly.

Generate certificates with CRL for Modern POS

If you are working with the Modern POS (MPOS) and experiencing issues right at the beginning with the activation of the device (if I recall right, because I haven't saved the error that I get, the message error code was something like: DC10031 or DC10032), one of the possible reasons for this would be that the certificates that you've generated do not contain a CRL (a short note: the process I'm describing below is strictly for a DEV, maybe TEST machine, never for a PROD instance).

Enable UAC from registry for MPOS

If you've started to work on MPOS, you know that it will only run on Windows 8 and 2012 machines with UAC turned on.