To get the answer to this run the following:
You have invoked the following:
alter <view_name> compile;
or
create or replace view <view_name> as .......<view definition>
When you did one of the above you got the "failed to compile" error, this is when you run this:
show errors
Each case is different, running 'show errors' will tell you what the problem is specific to each one.
Chat with our AI personalities