Sometimes, we may encounter the phenomenon that no traffics transmit between TP-Link smart/managed switch and other switches when they connected by SFP port. As shown in the following topology, the two switches are connected by the fiber, and the LED lights are lighting on, but there is no data transmitted between them.
Usually, this phenomenon may be related to the compatible problem. To help the consumer, we release an FAQ which has detailed the troubleshooting steps. If you encounter this problem, please refer to this link to know the Troubleshooting Instruction of TP-Link switch’s SFP port.