Inspect and clean SFP+ modules and fiber connectors regularly to prevent common issues like link failure and high error rates. Use vendor-approved SFP+ Optical Transceivers and keep your switch firmware updated to ensure compatibility and stable connections. The issue is when I plug multimode fibre in the module the link doesn't come up. Any reasons why it is happening. Why multimode fibre is not working with Multimode SFP Module? Someone suggested because MM. Before you escalate to a costly support call or initiate an RMA for a seemingly faulty multimode SFP module, it's crucial to understand that the transceiver itself is rarely the sole culprit. In my experience overseeing data center operations for over a decade, I've found that over 80% of multimode. The SFP/Media Converter is designed for easy use in optical fiber transmission. When the connection does not work as expected after we set it up according to the Installation Guide, we need to do some troubleshooting.