Can “STM32 ST-Link Utility” connect and program your chip ?
Can you verify that no debug session has been already launched. Go to the Debug perspectie (Windows > Open Perspective > Debug (or Other... > Debug)) then terminate every opened sessions.
Then relaunch the debug. If the same error is displayed, please copy the openocd process output (on the Debug perspective, select the openocd process under your debug session, the output should be displayed on the console view).
If OpenOCD initialization fail in reset procedure, you might modify your OpenOCD custom configuration script (*.cfg under the project) as following
reset_config none (instead of “reset_config srst_only srst_nogate”)
It did work for me when the Reset pin of the ST-Link is not linked.