Hi All,
Per this link, the GLC-SX-MMD should be compatible with the ISR4321/K9
https://www.cisco.com/c/en/us/products/routers/4000-series-integrated-services-routers-isr/relevant-interfaces-and-modules.html
However, this is the error that I rec...
Thanks for the response Leo Laohoo! The workaround described for CSCug11055 seems to have got things working for me now. Any particular reason why this shouldn't be used long term?