Can't build copper mine or wheatfield

As of this morning neither of these will build. I order them, and the place appears on the ground, the building licence count diminishes and the entry appears in the build queue at 0%. After about 30 seconds both just disappear and the licence is back. I haven't tried other buildings as I'm short of licences and don't currently need them. I have 2 building licences left, and 141 free settlers.

I've tried closing out and logging back in - no change.

Edit to add:- Just tried a wheatfield very close to the store house. The settler appeared and began building... he got to about 34% and then it just vanished.

Grateful for any help please, but off to work so won't be around for a while. Will close game and shutdown for the day.

Have logged on from work and building things is absolutely fine. Must therefore be a browser issue at home, which I hope the reboot might clear.