I observe that I had to go physically to the location then
a.) Power cycle the radio unit;
b.) Defaulted the radio unit to factory default settings
c.) after which I was able to upgrade the radio unit from 3.5.2 version now to 4.6.01 version. d.) Then after which I had to reconfigure the radio unit for the link to be back up and running.
I see you got this figured out but for future reference or anyone else in the future with a similar issue.I’ve run into this same issue before and for me it was a browser issue. When I switched browsers I was able to upgrade the firmware. I normally go back and forth between Chrome and Firefox so when I had this issue one worked and one didn’t.