Redmine

Several things could possibly be causing that, for instance:
1. Your workflow configuration somehow does not allow for any transitions
2. Perhaps your statuses are configured to be calculated based on subtasks, so that status is actually dependent on statuses of subtasks more than your selection on Status drop-down on your parent issue.
3. You're using a newly added custom Tracker that does not have any workflows configured for it in Administration section

If you could share more details and/or screenshots, I could possibly be more speific with my hints.

First of all, thanks to answer.
I have read again my post and I think my explication is so poor. Sorry so much.

If we use the web aplication of redmine all it's ok. It is possible to change the status of a issue, however if we use the mobile app RedminePM the only status that we can choose is NEW. When we edit an issue it's not possible to choose another status different than NEW. I don't know why.
I'm try to answer your post, sorry again for my poor English.
1) I think the workflow is correct, because all it's ok in the web application.
2) I don't think the statuses are configured to be calculated bases on subtasks, because we aren't using subtasks.
3) I think it's my poor english, but I don't understand your number 3 (if the workflow is ok in the web, I think it will be ok in the app, isn't?)

I have the problem in the mobile app redminePM. When I edit an issue, I can choose all the possible values of the different fields except status (only shows New - Nueva in Spanish-)

When I sincronize the master datas (in Spanish are "datos maestros", sorry for my translation) I only can see Nueva (New) in Status. I've atacched an image in the post where you can see I'm trying to explain with my English.

If you need more information or more images, please don't doubt to ask me.

Thanks again for your answer.

To be honest, I had mixed results with the free Redmine PM mobile app. Limited search results, lack of support for all types of custom fields, etc.

But Redminer app (for Android) https://play.google.com/store/apps/details?id=com.ideil.redmine is working great so far . I'm thinking you might have ran into a bug on Redmine PM mobile app. Try Redminer instead - I can't be certain that will solve all of your problems forever, but I can assure you it's worth a try.

The same here with Redmine PM App (Android 6)

Redminer is working