Please see Why are questions no longer being accepted from my account? from the Stack Overflow help center (or the equivalent page of any other SE network site) for more general information about question bans, how they work and what you can do to avoid them.
TL;DR: Post well received questions and also edit and improve your old questions to make them meet the respective site's standards of what makes a good and on-topic question. Consult the help center of each site, e.g. for Ask Ubuntu or Stack Overflow section. Pay attention especially to the pinned entries, those are most important.
If, after reading those resources and revisiting your own posts, you still don't understand why they were badly received, you may consider asking on the respective Meta site about what is wrong with those posts, i.e. Meta Stack Overflow for your SO posts. Do your own research first and explain what you tried though, else that question would just get downvoted and ignored again.
Regarding your question whether a ban from asking or answering extends over multiple sites from the network, no, it does not, or at least I could not find any indication that it does.
All question and answer bans are also handled fully automatic by an algorithm that takes your contributions on a site and how well it was received into account. Moderators can neither manually impose or lift those.