Can't access my local web server on Mac mini from Laptop after MX records update

I would check the network settings on the laptop and make sure the network adapter being used is correct and connected to the correct network.

If all the above appears correct, try renewing its DHCP lease.

You may need to dig deeper into Details in the network settings interface and make sure all is as it should be (TCP/IP,DNS, WINS, etc.)

You may even need to remove the network interface in Settings and then re-add it. It isn't common, but sometimes the network settings get corrupted and need to be "reset".

"Can't access my website on my local network: I run a web server on my Mac mini on my Wi-Fi network. Somehow, after adding some MX records to my domain provider, I can no longer access my server on my laptop. However, I can access it just fine on my iPhone and my iPad. Monitoring websites outside my network also report that my website is up. I tried cleaning website data from Safari and Chrome but both cannot access my website. What am I missing?"

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Troubleshooting a Computer’s Connections to a WiFi Network:

What does the Error Message Read:

Are you getting a “404” error message? If so, then there is an issue connecting to the server.

NemesysSoftware wrote:

Thanks for the suggestion but I'm not so sure. I rebooted my MacBook Pro in Windows 10. Chrome on Windows could not find my server either. So, I'm not sure removing the network interface would help...

Is Win10 running in a virtual machine or natively via Bootcamp?

If it is via virtual machine, if the Windows virtual machine is set up to share the Mac's network connection the test is not valid since the Mac is just forwarding from macOS to the Virtual machine.

If the the virtual machine is configured to look like a a totally different machine on the network or if you are running Win10 natively via a Bootcamp install, the issue is somewhere in your network or your server.

All this is assuming your MacBook Pro can access network and internet normally.

NemesysSoftware wrote:

It was running natively via Bootcamp. No virtual machine.

....

If it is happening both in Windows and macOS, then i would say the issue is with the network or your server not "liking" the Mac after changes you made to the server.

Is the Mac working normally on the network otherwise and it is just the server access that is the issue? If so that strongly points to an issue with changes you made to the server.

NemesysSoftware wrote:

It was running natively via Bootcamp. No virtual machine.

Here is the message Safari displays.

…

Okay. To summarize this, an unspecified web server running on Microsoft Windows or maybe Windows Server is inaccessible on the local network from macOS and Windows, and the web browsers on macOS and Windows browser clients are both reporting a server connection error.

Look in the web server logs, as a starting point.

You’re running a server, so logs are going to be a common troubleshooting resource.

I’d investigate whether your TLS certificate is incorrect, or maybe missing an intermediate certificate, or your server DNS might have a configuration issue.

Or Apache or IIS or whatever web server you’re running on Windows is unhappy, maybe due to the web server virtual host (this as differentiated from an operating system virtual host) the local browser clients are requesting, as differentiated from the web server (virtual host) the remote browser clients are requesting; configuration or certificate or DNS errors.

It’s also possible that the local Wi-Fi router or local network routing configuration is incorrect, or the router itself is confused. That if the connection isn’t getting to the correct Windows server box, or maybe the routing to or from the Windows server is getting tangled.

But this probably also isn’t the best place to seek help troubleshooting an unspecified Windows web server, and one probably related to a certificate or to DNS or routing issue.

With apologies, ASC crashed Safari, and recovery messed with the formatting of the following.

Okay, so this would best be in a DMZ or hosting the website elsewhere. This as hosting locally risks breaches behind the firewall. But if you’re mixing it all together with a server exposed to the ’net as I’d suspect, then this discussion is headed for some basic knowledge of IP and IP routing, and also some basic knowledge of Apache and its logs.

Apache can be set up in various ways including the built-in, various add-ons, and app packages such as MAMP, so I can’t point to a specific place or specific tutorial for your particular install, and the details of macOS and macOS Server (R.I.P.) have also varied over the years. I’ll assume you’re not running macOS Server here.

If it’s the default macOS Apache install or something close to it, then start with the following commands:

which apachectl
which httpd
httpd -V

That should show you some generic app configuration information, as well as probably showing the path to the error log files.

If not, then look for your httpd.conf file — wherever that is in your install — and look for the error log location directive in that file.

The default location for that Apache configuration file with the macOS (not macOS Server!) built-in Apache is:

/etc/apache2/httpd.conf

Probably finding this directive referencing the error log:

ErrorLog "/private/var/log/apache2/error_log"

Okay. Hopefully you've found your particular error log, and looked in it for errors related to the TLS certificate or the connection, or whatever else might be (not) happening.

The following describes the TLS certificate setup:

https://getgrav.org/blog/macos-sequoia-apache-ssl

I’ll leave IP and DNS troubleshooting aside for the moment, but that may be your next stop.

Did you check the error log for related errors?

NemesysSoftware wrote:

I'm sorry, I thought it would be helpful to check the access log and see if there was any activity from trying to access the website.

When something in the network or something in the server is blocking or dropping the incoming connection without showing even an error page, that activity probably won’t show in the access log.

What else should I try?

The error log.

There are undoubtedly some Apache troubleshooting documents around the ‘net, too.

NemesysSoftware wrote:

How do I check the access chatter originating from my local network?

Look for error log or other Apache log entries with addresses from within your local IP subnet, or alternatively shut off remote access into the web server at the firewall and test web server access (try to trigger the error) and then view the logs all during the remote-access pause, and then re-enable remote access.

Any add-on VPNs or add-on security apps or other potentially-routing-modifying apps present on client, or on server?

Router firmware current?

I don't know if you have tried this or not, but have you simply tried to PING the server computer from the laptop? This would quickly tell you if it is a network or server issue.

Have you tried using Wireshark?

I would try Wireshark and use the filter to limit the connection to the IP address of the server. Then, from the laptop, send the website request and see what traffic goes back and forth during that request. Generally one would see the initial request from the laptop and then handshaking traffic to setup the security connection and then followed the http response.

There could then possibly see if there is a TLS issue that may not be completing or if the server is even getting the request.

I have used Wireshark quite often in debugging embedded web servers, telnet, SSH, etc. and has helped to quickly find the issue.