If you need support from Yola please contact us via firstname.lastname@example.org or make use of our live chat service! We are working on a new approach to community-based support and during this transition period we are not adding any new threads to this forum. Many thanks to everyone who has participated over the years and we look forward to unveiling a new peer-to-peer support system soon!
If you are trying to add a 301 redirect for a specific page on your site, unfortunately we do not have a feature on Yola that you can use to do this. An alternative would be to create that page, make sure it's not included in the menu and then add a snippet of HTML that will redirect your visitors to another page. This link will explain how to do that: Links that redirect when you click on menu tab.
I'm afraid that it's currently not possible to customize/replace 404 pages with Yola. I'm sorry that I don't have better news on this matter for you at this stage.