I am getting this … tried several times … any ideas on how to fix it?
You can first click on the Update button on APPLICATIONS → Plug-ins page, then try installing LuCI again.
Update to 3.211, did the LUCI install like every other time without any issues.
When you have this problem, ssh to the router and reinstall luci
opkg install luci --force-reinstall
Thanks, this did the trick!!