Why isn't my email marketing list showing all my clients?

[Voetbalstacksnl]

hi guys, 

When i want to start a marketing campagne i just can't get my clients in the list. When i go to the customers page i see all my clients and when i save the list then it says that all the members are in, but when i open the e-mail i see this? 

how can i fix this?

[Voetbalstacksnl]

can any one help me please?