I noticed a sharp drop in Adsense earnings on one of my sites this week and after a bit of digging in the Search Console found errors suggesting there was a problem with my robots.txt. I checked this and it is absolutely fine.
When I went to the old console and ran some fetch as Google (desktop) I got Unreachable for all the URLs I tried on that domain (including /). However, when I tried the mobile crawler all were fine, including rendering.
A bit of background. I host several websites on a shared IP address. I recently moved server / IP address. This was about 4 weeks ago and I haven't had any issues until a few days back, and only on this site.
I do run application firewalls (Fail2Ban and mod_security), but again these shouldn't have changed suddenly. Plus I have now disabled them.
I have checked the site from a few IP addresses to check it is working properly and it is.
Any ideas - or is it it just a wait and see...