I've experienced the same problem as you in the last few days but i have not received a solution yet.
I raised the ticket 2 days ago....
Originally they reported our server was not setup correctly however this cannot be the case because within the same campaign some emails / links work and others do not even though they were tested prior to sending.
Update: Help desk. Got back to me, but were unable to duplicate the error....Official result is that the email wasn't saved properly are something to that affect. I do disagree with that assumption for the reason I stated earlier (the live test, the link did render properly). I'll continue to monitor this going forward to see if there is a glitch (if any).
Just experienced this across multiple emails. Obviously something is wrong in Eloqua and they don't want to admit it.
Sorry for the delayed response...There must be a glitch. I was also told that the email wasn't saved properly also, which wasn't true. The email was saved properly as we did multiple tests throughout the day and the email image and links were functional.
Going forward since then we have not ran into that issue. As a best practice, we execute a soft launch within the campaign to my seed list. So if we schedule a launch on Tuesday, we'll do the soft launch as earlier as 24 hours before to the seed list (or to myself and a few trusted colleagues) before a full launch.