Direct answer
For the Canon MAXIFY GX4020, printer radio, supported band/security, setup mode, router isolation and account/app should be separated. First, print network status and place printer near the router.
What this covers
- Canon MAXIFY GX4020 (5779C002)
- Canon printer; PIXMA/MegaTank/MAXIFY/imageCLASS ink/toner systems and maintenance paths differ.
- The specific fault this record addresses: will not connect to Wi-Fi
What it does not cover
- ×The same symptom on a different Canon product line, which has its own record and its own cited source
- ×An on-screen error code whose meaning has not been checked against this exact model's manual
- ×Live electrical, gas, sealed-system, internal battery-cell or structural repair — a technician boundary, not a self-service step
Differential
What actually causes this, and how to tell them apart
These are ordered by how often each one is the answer, not by how easy it is to try. The point of the middle column is that two causes producing the same headline symptom rarely produce the same detail — that detail is what tells you which one you have before you change anything.
- 1
The printer cannot see a 5 GHz network
What separates it The printer's network list is empty or missing the home network, on a phone connected to 5 GHz.
How to confirm Most printers are 2.4 GHz only. Where a router broadcasts both bands under one name, the phone silently prefers 5 GHz and the printer cannot see the network at all.
- 2
The phone is on a guest network or isolation is enabled
What separates it Setup appears to complete but the printer is never reachable afterwards.
How to confirm Guest networks and client isolation prevent devices communicating, which is exactly what printing requires.
- 3
The password was entered incorrectly
What separates it The printer reports an authentication failure.
How to confirm Entering a long password on a printer's own keypad is error-prone, and the printer will not say which character was wrong.
- 4
The printer is still in setup mode from a previous attempt
What separates it Setup will not restart, or a direct setup network is still being broadcast.
How to confirm Reset the network settings on the printer and start once, cleanly, rather than layering attempts.
- 5
WPS is being used and the router does not support it
What separates it WPS push-button setup times out.
How to confirm Many routers now disable WPS for security. Use the manual network entry instead.
- 6
The connection succeeds but the address keeps changing
What separates it It works after setup and stops days later.
How to confirm See offline — assigning a fixed address in the router prevents this.
Before you touch a setting
Record this first — changing settings destroys the evidence
Every item below stops existing the moment a reset, re-pair or settings change is made. Written down first, they are what separates the causes above; recovered afterwards, they are guesswork.
- Whether the printer's own network list shows the home network at all.
- Which band the phone or computer is joined to during setup.
- Whether the network is a guest network.
- The exact error the printer reports — authentication and not-found are different failures.
Join the phone or computer to the 2.4 GHz network explicitly
ReversibleMost printers cannot see 5 GHz at all, and phones prefer it silently when both bands share one name.
Use the main network rather than a guest network
ReversibleGuest networks and client isolation block exactly the device-to-device communication printing needs.
Reset the printer's network settings and run setup once, cleanly
ReversibleLayered failed attempts leave the printer in an inconsistent state.
Enter the network name and password manually rather than using WPS
ReversibleMany routers now disable WPS for security, and it fails by timing out with no explanation.
Assign the printer a fixed address in the router afterwards
ReversibleThis prevents the connection working today and failing next week when the address changes.
Model-specific
What is true of this model and not of its siblings
Generic advice for the product line fails here. Each item below is a property of this specific model family that changes which of the steps above apply to you.
- Model scope
- 5779C002. Canon printer; PIXMA/MegaTank/MAXIFY/imageCLASS ink/toner systems and maintenance paths differ.
- Type — BUSINESS refillable INK TANK all-in-one (MAXIFY)
- A business MAXIFY MegaTank AIO — refillable ink BOTTLES with pigment inks and office features, below the GX7021 in speed/capacity. Still inkjet, so the printhead can CLOG if unused.
- Pigment ink + volume
- Pigment inks for durable documents; very low running cost. Don't run tanks dry; initial charging uses some starter ink (normal).
- Connectivity
- Wi-Fi/Ethernet/USB via the Canon app; 'offline' is usually a network/queue issue.
- Symptom boundary
- This record covers Canon MAXIFY GX4020 when it will not connect to Wi-Fi. A different symptom on the same hardware, or this symptom on a different Canon product line, has its own record with its own causes and its own cited source.
Stop boundary
When this stops being a self-service repair
Continuing past any one of these costs more than the repair saves — in safety, in warranty, or in evidence a technician needs.
- !Do not weaken router security, disable encryption, or move to an open network to get a printer connected.
Evidence ledger
Sources behind this answer
Visible sources support the visible claims. Home Product Support records the publisher, the fact used and the review date; community reports can suggest an issue but do not become a published fact on their own.
Where the manufacturer's article stops. Canon publishes this as "How to Reconnect Your Printer to a Wireless Network (Windows)". Canon's procedure for a printer that has dropped off or will not join the wireless network. Probed 2026-08-21: title-verified. What that article does not carry is the model boundary — it is written for a product line, and 5779C002 is the scope applied here. Where a control label, terminal, indicator pattern or reset sequence differs on your unit, the manual for that exact model is the authority, not this page and not the article.
Exact questions
Common follow-ups
My Canon MAXIFY GX4020 prints faded with full ink tanks.+
That is a printhead clog — the MAXIFY is a refillable inkjet, so full tanks do not prevent clogs, especially if it has been idle. Run the nozzle check then Cleaning and, if needed, Deep Cleaning from the menu/software, printing a pattern after each to gauge improvement. Make sure no tank was run dry (air in the lines clogs it). Print regularly to keep the head clear. The pigment ink and tank refills keep running costs very low for office use.
The printer can't find my Wi-Fi network at all.+
Your network is almost certainly 5 GHz on the device you are setting up from, and most printers can only see 2.4 GHz. If your router broadcasts both bands under one name, your phone will have silently chosen 5 GHz. Connect the phone explicitly to the 2.4 GHz network before running setup, and the printer will see it.
It connected during setup and stopped working a few days later.+
That is the printer's IP address changing when the router reassigned it. Assign the printer a fixed address in the router's settings — it takes a few minutes once and prevents the problem permanently, rather than reconnecting it every few weeks.
Does this answer apply to every Canon model?+
No. It is scoped to 5779C002. Canon printer; PIXMA/MegaTank/MAXIFY/imageCLASS ink/toner systems and maintenance paths differ.
What should I record before troubleshooting Wi-Fi or wireless setup?+
Record the complete model identifier, exact message or indicator, software/firmware where visible, the operating stage and what still works.
Why is a factory reset not the first step?+
A reset can erase accounts, networks, maps, schedules or preferences without distinguishing Wi-Fi, wireless setup. The ordered checks preserve that evidence.
When should I stop and use qualified service?+
Do not weaken router security or publish network passwords.
Answer for the exact device and software version shown above.