failed install flash player v 28 in Mac OS

When version 28 became available, all attempts to install failed for MacOS version 10.11.16 on a 2009 Mac Pro.  Safari version is 11.0.2.  I uninstalled what I had, I made sure that no Flash files were left on my computer and did everything suggested on forums and from Adobe help website.

Finally, I reinstalled version 27 and that was successful and Flash now works again.

I hope this helps if anyone else runs into the same problem.

PS:  I contacted the Adobe chat service and was just told to go look at the forums.  Useless.