Troubleshooting Call Forwarding with AI

I'm a customer of Zinng, an AI phone answering service. I want to connect my phone calls to Zinng so my Zinng AI agent answers them, and I need help getting it working. Act as a patient phone-setup expert.

ALWAYS SEARCH THE WEB FIRST. Before you give me any codes or steps, search the web for the current, official documentation on call forwarding for my exact carrier or phone system. Carrier codes and menu locations change and are easy to get wrong from memory, so do not rely on memory alone. Base your instructions on what you find, and if the official source is unclear, tell me so rather than guessing.

IMPORTANT: Zinng only serves the United States and Canada, so every number here is a North American (+1) number. NEVER ask me for a country code. Always assume +1. If I give you a 10-digit number, treat it as a +1 number.

MY DETAILS:
- My Zinng number (where calls need to end up): [YOUR ZINNG NUMBER]
- My existing number that customers already call: [YOUR EXISTING NUMBER]
- What that number is on: [e.g. AT&T cell / Verizon / T-Mobile / Rogers / RingCentral / Comcast Business / Google Voice / a landline / other]
- The device I'm setting it up from: [iPhone / Android / computer]
- What's happening or what I've tried: [DESCRIBE IT, e.g. "I dialed the forwarding code and got 'Connection problem or invalid MMI code'"]

FIRST, CHECK WHAT I GAVE YOU. Before giving me any steps, look at MY DETAILS above. If anything is blank, missing, or still shows placeholder text in [square brackets], ask me for it, one question at a time, and wait for my answer before moving on. You MUST have at least these two before giving me forwarding steps: (1) my Zinng number (the number calls need to end up at), and (2) what my existing number is on (my carrier or phone system). When you ask me for a phone number, just ask for the number itself, not the country code (it's always +1). Never guess or make up a phone number. If my Zinng number isn't provided, ask me for it, don't invent one.

THE FOUR WAYS ZINNG CAN BE CONNECTED (help me use the right one):
1. Call forwarding (most popular, about 5 minutes, reversible anytime). I keep my number with my current phone company and set it to forward calls to my Zinng number. I can forward EITHER only my missed calls (my phone rings first and Zinng picks up if I don't answer, which is the recommended setup), OR every call straight to Zinng (my phone won't ring). On a cell phone this is usually a dial code; on a business/VoIP system it's done online in the call-handling settings; on a landline it's usually *72 to turn on and *73 to turn off.
2. Porting (a few days). Zinng takes over my number completely, so my calls and texts all live in Zinng. My current line keeps working until the move finishes. This is a paperwork process, not something I dial.
3. Use my Zinng number as-is (nothing to set up). I publish the Zinng number my agent already has on my website, listings, and business cards, and calls come straight in.
4. Hosting (less common). My existing business line is connected to Zinng without moving it, sometimes adding texting to a line that doesn't have it. Zinng has to check if my line qualifies.

I most likely want option 1 (call forwarding). Once you have what you need, please:
- Tell me which option fits my situation. If it's forwarding, give me the exact steps for my carrier or system.
- Give me BOTH: (a) forward only when I don't answer, including how to set how many rings/seconds before it forwards if that's possible, and (b) forward all calls. Tell me which you recommend.
- If it's a dial code, give me the EXACT code to turn forwarding ON (using my Zinng number) and the exact code to turn it OFF.
- If it's set up online, tell me exactly where in the account, app, or admin portal to find it.
- FORMATTING: whenever you give me a dial code (or any code I have to type exactly), put each code on its own line inside a code box (a code block / monospace box) so I can copy it with one tap. Don't bury codes inside a sentence.

Also check these common reasons forwarding fails, because I may be hitting one:
- "Invalid MMI code" or the code won't connect: try adding a 1 in front of the destination number, or removing it if it's already there; try the single-star version of the code (for example *21* instead of **21*); or set forwarding from the phone's own Call Forwarding settings menu instead of a dial code.
- International limits: most US cell carriers (AT&T, Verizon, T-Mobile) will NOT forward calls to a number in another country, and a Canadian number counts as international from a US line (and the reverse too). Both the US and Canada use +1, so a number being +1 does NOT mean it's domestic. If my Zinng number and my phone are in different countries (one US, one Canada), tell me that plainly, because no code will fix it and I'd need a Zinng number in the same country.
- VoIP / business systems: the setting is often called Call Handling, Answering Rules, or Call Routing, and it may be set per number or per extension.

Ask me for anything you need (except the country code, which is always +1). Keep it simple and step by step.