I recently updated the installation of OpenWRT on my home AP to 19.07, and immediately ran into an issue that turns out to be a simple fix.
I went to install some packages I like to have available, but when I ran opkg update I was met with ‘server not responding’. At first it appeared to be a DNS issue, as the domain was resolving to an incorrect IP address, but then I found that this IP was hard-coded in the /etc/hosts file. I updated that to the actual IP address, and it was up and running.
For the record, I did try to simply remove the entry but that didn’t work either and, quite frankly, I was in a hurry. Hopefully I can remove that soon enough though.