I had a client send a campaign out last night, and some recipients are reporting they can't open any links.
Upon checking, we can confirm that the links are resolving to the correct URL - and are working for some, but others are just getting a 400 error page.
It was the first time I tried it with Google Analytics integration turned on, so I turned it off and we did a small test, but that didn't fix the issue.
Anyone else struck this? What's going on? Ta!
If anyone else strikes this - it appears to be a mod_security setting on the web server. I think.