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try without emoticons
I think this is the problem here

no, that's not it.
I tryed another post with links again and it didn't work as well. no emoticons

somewhere is a problem...
must be a solution to this strange situation

first I couldn't comment as well
log out and log in and then restart browser. after that it worked.

but not the blog post...

seems to have recovered....ok from what see i can comment and post but can not use emoticons in the post
try without linking inside your post

https://steemit.com/news/@kubrickkk/missing-posting-authority
here I found the solution for me, comment of ace108, it was the tags
had to type instead of copy paste them