I created an AB test and created a modal to appear as visitors first enter site on homepage using the code editor. The variations appear as they should in the editor and the browse function, but do not appear in the preview links or live on the site when the test is active. I recreated the test in a new activity and was more specific on the audience, but the variations still do not appear in the preview or live. Is this an mbox issue, a coding on the site issue, or a code editor issue?
It looks like you are trying to load Target on that page with Adobe's DTM; however, your script reference to DTM is returning a 404 error. Consequently, Target is not loading on this page. Which explains your issue of never getting into a test via preview links or otherwise. Please check your DTM tag on the page. You can find it by looking for the script pointing to "//assets.adobedtm.com/...". If you can update that so it correctly points to your DTM instance, and verify Target is implemented via DTM you should start seeing your test with the preview links.
Okay, if you aren't seeing the mbox request fired from the page (a call to *.tt.omtrdc.net/) then it is likely an implementation issue. If you add "?mboxDebug=1" to the end of your URL and reload the page you should get a pop up (if using mbox.js) or console logs (if using at.js) are you getting any error message there?
If you are able to share the URL I'm happy to take a look at it to provide any additional suggestions.
Hard to say exactly what might be going on, I've seen varying cases. Here's what I'd check:
Can you see the expected code returned in the mbox request call? View it in the network tab of the dev tool for your browser. Chrome provides a "preview" mode for looking at response bodies. This is nice for JSON responses. Do you see the custom code you added in the test coming back to the page?
If the code isn't coming back, then it's possibly a preview link issue. Are your preview links for the correct experience? Try to "renew" the preview links and check again.
If it is coming back, I'd check your custom code. If it's JS then you can run it in the console of the dev tool to verify it works on the page.
Hope that helps. Let us know if you have additional details.