Hi Hendrik,
there are a few issues in your flow:
1. you should update line 18 in your metadata.xml. the namespace of the entiryType is missing the "de" in the beginning.
<EntitySet Name="privmailinfoset" EntityType="de.mindsquare.privmailinfo"></EntitySet>
you can easily find semantic issues in your metadata by using the OData Model Editor
2. you are missing the model declaration in the manifest.json file. please add the following under "sap.ui5" -> "models"
"": { "dataSource": "mainService", "settings": { "defaultBindingMode": "TwoWay", "defaultCountMode": "Inline", "refreshAfterChange": false }
Best regards,
Elina