Why can't I see a specific customer or sales opportunity?

Being able to view sales opportunities in general does not mean that you can view all of them. Access is assessed for each listing.

Ownership

Many roles only give you access to records you own. If the record is assigned to a colleague, you won't see it—even if you know it exists.

Business unit

Roles can be restricted to your own business unit. A customer owned by another department will then be hidden from you, which is usually intentional.

Sharing

A record can be shared with individuals or teams without changing ownership. If you need permanent access, sharing is often the right solution rather than changing your role.

Search only shows what you have access to

If you get no results for something you know exists, it is almost always an access issue, not a search issue. Ask the owner of the record to share it, or ask an administrator to review your role.