My iMac will not connect to Brother printer after replacing WiFi router.

Have put your question to an AI / LMM to see what it says 

I do not take credit though,  having setup an AirPrint Epson ET -2750 Printer / Scanner

The instructions seem about the same as when I manually setup the printer /scanner

M4 Desktop with macOS  Tahoe 26.0.1

Below is what it does suggest

Reconnect Your Printer to Wi-Fi Correctly

Let’s re-do the Wi-Fi setup from scratch. Choose the method that suits your printer:

Option A: Wireless Setup Using Printer Control Panel

1. On the printer's control panel, go to:
2. Menu → Network → WLAN → Setup Wizard
3. When it asks if you want to enable WLAN, choose Yes.
4. The printer will search for available networks. Select your correct Wi-Fi network name (SSID).
5. Enter your Wi-Fi password carefully.
6. The printer will attempt to connect.

• If successful, it will say Connected.
• If not, it may give the TS-02 error again — this usually means wrong password or incompatible Wi-Fi band.

✅ Tip: Make sure your router is broadcasting on 2.4GHz (not only 5GHz). Many routers have both bands; sometimes you need to enable or split them manually.

3. Restart Everything

After re-connecting the printer:

• Turn OFF and ON your:
• Mac
• Printer
• Router

Let them all restart cleanly to flush out connection issues.

Add Printer Again on Your Mac

Now let's ensure your Mac sees the printer:

1. On your Mac, go to System Settings → Printers & Scanners
2. Delete the old printer entry (if it’s still listed)
3. Click the + button to add a new printer
4. Wait a few seconds to see if your Brother printer appears in the list
5. If it shows up as Bonjour / AirPrint, select it and click Add

⚠️ If the printer doesn't show up: it’s not properly connected to Wi-Fi.

5. Use Brother’s Wireless Setup Utility (Optional but Helpful)

You can download Brother’s Wireless Setup Utility on your Mac to automate the Wi-Fi setup. Here's how:

1. Go to Brother's official support site: https://support.brother.com
2. Enter your printer model
3. Download the Wireless Setup Utility for macOS
4. Follow the on-screen steps — it will walk you through Wi-Fi configuration using a USB cable (if needed)

6. Optional: Print WLAN Report

You can usually print a network report from your printer’s menu:

• Go to Menu → Print Reports → WLAN Report
• This printout will tell you if the printer is connected, and show the SSID it’s on
• If you see TS-02, it confirms it couldn't detect the access point

Specific to Brother printer HL-L2305W.

https://help.brother-usa.com/app/answers/detail/a_id/185118/session/L3RpbWUvMTc2MDM1NDg1Ni9zaWQvMkY0YnpRZnI=?_gl=1*waemkw*_gcl_au*MTU5ODg3ODY1Ny4xNzYwMzU0ODE3*_ga*NTk3MTI5MTA4LjE3NjAzNTQ4MTc.*_ga_NCEW43SJ8W*czE3NjAzNTQ4MTckbzEkZzEkdDE3NjAzNTQ4MjkkajQ4JGwwJGgxMjMxNjQ2MjQ5

meredith284 wrote:

Thanks. Yes, I have done all of the above. The computer is recognising the printer and shows a green 'button' and the comment "idle".

At one stage the printer was showing 'deep sleep' so I tried all the suggestions on the brother site and ended up deleting the printer from the mac settings and re-installing it.

I've tried all of the suggestions you make ... but guess I'll have to try again. There has to be a simple solution but just at the moment I cannot seem to find it. Appreciate your help.

Perhaps if the user was less vague as to exactly which of the hundreds of Brother Printers this printer might be

We may or may not be able to assist further

Did you already check this Brother Support page about this error?