1. After log in CM go to forms and see the form you saved it is visible or not , then try to edit the form , check all fields are showing ,
2. If you have write any custom save action method then check by removing the custom save action code is not throwing any error , or simply assign one ready made action avialable with sitecore forms like redirect to page or some other ,then publish and see the forms fields are showing in CD or not .
3.Check the CD environment is connecting with solr right url with https .
4. Last part follow the above mentioned document you are using right data source for the form in your mvc layout(Renderings/System/Forms) component or not
I think some small thing is missing , please let me know if you able to solve this
If you are using sitecore 9 , then please check the following things :