As far as I can see, when a MobileFrontend edit fails because of a spam blacklist failure, the message shown is "Error, edit not saved."
This is not helpful for understanding the reason why it failed. Earlier today I spent some time helping a user who tried to make a constructive edit to an article and kept seeing this cryptic message. Thanks to our stubbornness, we eventually found out that the problem was that the edit included a link to youtu.be, which is functionally harmless, but nevertheless globally blacklisted for technical reasons. The edit eventually worked with youtube.com, but I suspect that many users who aren't as stubborn as we were while debugging it just give up on editing.
It would be much easier if the message clearly explained the reason for the blocking, as it is done in desktop.