look when you are previewing what ‘stage’ and ‘role’ the form is running in. when you deploy the form and load it, it will be in the first ‘stage’ of your form and the ALL role. If these are different then review your field states. if the objects you are trying to write into are ‘disabled’ for instance you will not be able to write into them. but also it could be if you have written your behaviours under a condition that isn’t being satisfied in this stage/role.
look also at the ‘debug’ function where you can select the stage and role for the form and then preview in ‘debug’ mode where you will then see all the form actions listed out in the debug pain