Unable to post on my Google+ time line

You should be getting some additional information along with that message - a link to the Policies ( http://www.google.com/intl/en/+/policy/content.html ) and a link for reconsideration request. Apply for reconsideration. 

The most likely reason according to me is that someone has reported your post. See the answer by a Google employee here : http://productforums.google.com/forum/#!topic/google-plus-discuss/oq4rVu34QJo 

we manually review when the Google+ community reports content through our Report abuse feature, and the appeals process varies in time depending on the violation and other factors. If you appeal the violation on 2 posts, only those 2 posts will be re-reviewed by our team. 

It might also be an automatic block based on heuristics like posting excessive links.

Also, according to their Terms, holding contests on G+ pages is not allowed.

Can you tell what is the content of that Google+ post which is being blocked?

Normally I posted my blog post that contains recipe. Have  sent the same post to  a few communities  after I  discovered other bloggers did this. As of now, unable to post on my own time line as well as to all communities.

If I apply for reconsideration, how long  it takes to  lift the ban?

Thanks  for your guidance.

If I apply for reconsideration, how long  it takes to  lift the ban?

I don't have any idea about it.  I don't use G+ and whatever information I gave was based on what I found googling the problem. 

Just apply for reconsideration and see if it solves your problem. If it doesn't post your problem on the official Google+ forums. Some Google staff answer questions there. So, they may look into your problem.