If you want help figuring out why things don't work then you need to provide better details than "common home router".
What I would do is find the exact manufacturer and model number, use google to find the user's manual, and then read the manual looking for the section(s) on configuring the WiFi access through the web UI. I would also look for a manufacturer supported user forum or the manufacturer's website and look for their support options.
My guess is that there is one check box (or dropdown) that needs to be changed to solve your issue, but finding that option with the information you have provided is impossible.
Earlier in the OP's diagnostics there was a mention of Fritzbox; Yes, a common router in Europe.... Not common in the US.
Would have been helpful to mention he was going through a router. Most Frizboxes are given to internet subscribers by their ISP as configs are easy to push to said routers from an administrative standpoint.
All that aside, Thanks folks as it gives me something to look for in my own case which is identical to the OP's situation.
I’m having a similar problem. My octopi is sitting on the same network as my computers. I checked on the router and got the actual IP address assigned to the pi server. When I enter this into a safari Browser, I can’t connect. Can I not access fri]om an iPad browser?
What did you enter into Safari for the address? Just the IP or prefixed with "http://" or "https://"?
I tested this on my iPad with two instances and Safari, just entering the IP of the Pi. Both times I reached the login prompt to enter my username and password.
I have tried with two different routers. one and Orbi network mesh and the other with Bell Canada fiber. using two different images of octoprint. nothing.
@walterlayher has suggested the most probable cause for this issue, a WiFi security feature in your router which prevents devices connected to it from communicating with each other.
You need to connect to your router's web UI and check for this feature. If your router has ethernet connections as well, using an ethernet cable may help us troubleshoot the problem. If you have an HDMI monitor and a USB keyboard, you can connect these to the Raspberry Pi which is another opportunity for troubleshooting.
While we are lacking in details on your configuration, it sounds like you have an iPad and some other Apple device. Determine the IP address of the other Apple device, install a ping tool on the iPad and see if those two can see each other.
If the problem hasn't been solved by now. The we are going to need a lot more details about your network. What devices are connected, what OS versions, what routers by make and model number, etc.