When using a SAP system topology where the SAP Gateway does not run the SAP DIALOG process, and registering a new Logic App SAP trigger, you may get the SAP failure:
ERROR Gateway not connected to local R/3
This is happening because Logic Apps is providing the SAP Gateway information for the RFC server registration as part of the RFC client connection (aka SAP destination parameters) used to retrieve the SAP system attributes and SAP RFC, IDOC & BAPI metadata. Although the SAP Gateway information is a server connection information, it is taken in account by SAP NCo for the client connection, resulting in the connection call been redirected to the SAP Gateway host which fails it in the absence of DIALOG process.
We have validated a fix for this issue with a customer affected by this and will be integrating the correction in an upcoming update to the On-Premises Data Gateway. In the meantime for using the Logic App SAP trigger, either ensure that the SAP Gateway host is also running the DIALOG process or contact our support to request access to a private early drop for the upcoming fix.