When adding content and something goes wrong, there are some basic troubleshooting steps you can do in order to dertermine if an error is caused by Ektron, your code, or your database.
You will want to test using a clean Page Builder template and/or Content Block template,create a Min Database, that is a clean database with only default information, and a Min Site which is the default site installation. Please find the steps below to create a min database and a min site for the testing.
NOTE: We highly recommend to back up any existing databases that will be replaced with a min-database before proceeding. This will cause the site that is being connected to the min-database to go "down" until the sync has been completed successfully. As such, we also highly recommend to perform these steps during an "off hours" or "scheduled maintenance" period.
First, create a Min Database, following this guide: /hc/en-us/articles/115004122086-how-to-create-a-min-database-for-esync
When you have it created, you'll want to configure your site's Web.config file to connect to that Database instead of your current one. To do that, edit the Web.config file and find the key labeled "Ektron.DbConnection". Edit that connection string to connect to the new database with the proper server, database name, user name and password to access it.
Now that your site is using the Min Database, try to replicate the error you were previously seeing. If you can not, then it shows the issue isn't with the database itself. In that case, you'll need to then create a Min Site for testing, using this article:
Once you have created the Min Site, once again try to replicate the error. If you can not, then it's not the base Ektron system causing it and instead is most likely your code. You should connect the site to your old database instead of the Min Database by updating the Ektron.DbConnection key in your Web.config file, and try again.
Additional things to check are:
Verify your WSPath: http://world.episerver.com/kb/10367
Check IP Restrictions: http://world.episerver.com/kb/10234
Make sure your Application Pool Identity in IIS is set to NetworkService and the folder (including subfolders) are allow Full Access permissions to NetworkService.
If you still can not replicate or resolve the error, please contact support for assistance.