I have a sample post that returns 500 error when I try to read it, and I cant create posts with a new user, same 500 error.
I suggest you use vanilla 2.1.11 since 2.2 is BETA and is for developers.
I may not provide the completed solution you might desire, but I do try to provide honest suggestions to help you solve your issue.
it is 21
then why are you posting in 2.2 category??
the assumption is if you don't mention version and you post in a category vanilla 2.2 help, it is the version 2.2 you are asking the question about.
500 errors - you would need to check error log.
turn on debugging.
verify if .htaccess is correct. etc.
post your questions in correct category next time, and I won't get confused
I enabled debug & found it was some plugins- removed & still have different errors now.