You can progress missions as you please but there will be a point that you can't complete anymore. The reason being that the missions require you to fulfill requirements that have not been released as content yet. For instance, some of the missions require you to complete stage 20 of the dungeons, currently only up to stage 15 exists. They'll be released in a future update and you will be able to complete those missions then. All the missions are can be completed at any time (except missions that require clearing the keeps, as they are only open on specific days of the week).

Did you ever get through the missions? I finished normal without completing them and it sure seems like they are frozen. I tried every combination of atk and nothing pops.

I have same problem. I'm on brutal and didn't complete missions before completing normal. I want my Arbiter. As this is an ongoing problem there should b some compensation for the level of prizes for the missions. Heck i Will go thru every one and show my completes if someone would respond to me. 

Also im on mobile and can't create a ticket or send to support. That blows for the lvl of money I spent. 

Hey Hey 

This is an old topic and made sense when current missions weren't directly available as they are now, they have all been released

As anything new should be a new thread, please note due to this i'm closing this thread.

Many thanks and Good luck