My entry does not appear on the site
Almost always one of three things: the entry is not published, the site was never granted access to that collection, or the site is showing a cached copy. Check the entry's status first — it is the cause in most cases — then the site's per-collection permissions, then caching.
Requirements: access to the collection in question, and — for the second and third checks — a role that can manage website connections.
You added an entry, it looks right in the CRM, and your site does not show it. This is one of the most common things to run into, and it is nearly always one of three causes. Work through them in this order — the first accounts for most cases.
1. The entry is not published, or not in its window
Every entry carries a status, and only published entries are meant for the public. An entry left as a draft or unpublished is complete and visible to your team but deliberately invisible to visitors. Two dates can hide a published entry too: a start date in the future means it is scheduled and not live yet, and an end date in the past means its window has closed. Fix: publish the entry, and check its start and end dates.
2. The site is not allowed to read that collection
A connected site is granted access collection by collection. If the site was set up to read your products but you have since added a new collection — services, say — the site has no permission to read it, so the entries never reach the page even though they are published. This is easy to miss precisely because it is not an error you see anywhere; the collection is simply absent. Fix: open the website's connection settings and grant read access to that collection. Changing the site's permissions ends its current access, so the site has to reconnect before it sees the change.
3. The site is showing a cached copy
Many sites cache their pages for speed, and a cached page keeps showing what was true when it was built. If the entry is published and the collection is granted, but the page still looks stale, the page has probably not been rebuilt or its cache not cleared. Fix: clear the cache or trigger a rebuild on your site. To make it automatic, see rebuild your site when entries change.
Still missing?
Three less common causes are worth a look. If the entry is filtered out by the page itself — a category, a date range, an "in stock" condition — it may be published, permitted, and fresh, yet excluded by the query behind the page. If a field the page depends on is empty, the site may be skipping the entry rather than rendering it half-built. And a secret field is never sent to a website, so a page that expects one will always find it empty. Check the page's own logic before assuming the problem is in the CRM.
Related
How a site reads your records is covered in using Sonta as your site's backend and how collections power a site; what publishing controls, in status and publishing.