I was testing migration of a SP 2010 site which used OWA to a SP 2013 environment. All was going well until I tried to open a word document and I saw this dreaded error:
So fire up the search engines wearing your trouble shooting hat. And you will get tons and tons of posts in similar line.
Finally, I saw this post:
Sorry, there was a problem and we can’t open this document
This has a lot of suggestions. But after spending hours and hours, one line caught my attention:
“Does the url work from the WAC server”
Now I am not sure what “the url” refers to. But I presumed that must be the url of the restored site collection. In my case I did not have a DNS entry and was using a temporary entry in my host file. I made sure I enter the same entry in the OWA server and do a ipconfig /flushdns.
And bingo! The above error was gone!