While login to MC getting the error "Invalid vendor string"

While login to MC getting the error "Invalid vendor string"

Issue: 

While login to MC getting the error “Invalid vendor string” as shown below:

Cause: 

This error occurs when Customer ID is not placed correctly after installation of iVend when customer id pop-up appears in MC.
The Customer ID details come with the license information shared by the licenses team.

Resolution Steps:

To resolve this issue follow the below steps:
1- Return the license using the Rehost option, also check if the license is in the broken state or not in license information.
If the license is in broken state contact citixsys support. If not, then follow the next step.

2- Activate the license.
3- Stop the license service.
4- Restart the license service.
If the issue persists after following the above steps contact citixsys support with license information.