The scenario runs Google Forms, then a router, Google Sheets, OpenAI Generate a response, an HTTP Make a request to Signatoro, and Gmail Send an email.
Why doesn't Make add my Gmail signature?
Make's Gmail module sends through the Gmail API, and the signature saved in Gmail's settings is only added to messages you write in Gmail itself. That is the whole reason the lesson fetches the signature from Signatoro. If you skip that step, the email arrives unsigned, or worse, signed by the AI.
What are the most common mistakes?
| # | Mistake or error | Fix |
|---|---|---|
| 1 | HTTP 401 missing_api_key | Start API Key with Bearer, one space, then the key |
| 2 | HTTP 404 no_signature | Click Save signature on Signatoro first |
| 3 | Gmail 403 insufficient authentication scopes | Reconnect Gmail and tick every permission, including sending |
| 4 | Asking ChatGPT to sign the email | End the prompt with a closing line and no name |
| 5 | Max Output Tokens set very low | Use 2000 so hidden reasoning doesn't eat the reply |
| 6 | One long paragraph in Gmail | Ask for <p> tags and set Body type to Raw HTML |
| 7 | Mapping the whole bundle instead of html | Map html from the HTTP module's Data |
| 8 | Key pasted into the prompt or a note | Keep it in Make's connection with Allowed service origins set |
| 9 | Switching on without reading test replies | Run several realistic tests, or send to a draft first |
How do I fix HTTP 401 missing_api_key?
1. In the HTTP module, Authentication type is API key and the connection is named Signatoro API key. The API Key value must be the word Bearer, one space, then your key. Paste the key alone and Signatoro can't read it. The rest of the connection: API key placement set to In the header, API key parameter name set to Authorization, and Allowed service origins set to https://signatoro.com. That is how a bearer token travels in a header.
You create the key on Signatoro under For tools and assistants, with Generate API key.
How do I fix HTTP 404 no_signature?
2. Signatoro has nothing to send until a signature is saved. Open your signature page, fill in Your details (Name, Title, Company, Phone, Email, Website) and click Save signature. Then run the scenario again. The HTTP module's operation bubble should show Status Code 200 and the signature.
How do I fix Gmail 403 insufficient scopes?
3. The Gmail connection was made without permission to send. Reconnect Gmail in Make, and on Google's screen tick every permission it asks for, including sending email.
Try it free, step by step
Add AI to Make.com: ChatGPT Writes a Personal Reply, Gmail Sends It. Connect OpenAI to your Make scenario, have ChatGPT write a personal reply from each patient's form answers, add the sender's real Signatoro signature, and send it with Gmail. You do every step yourself in a practice copy of Make, it checks your work as you go, and “Do it for me” finishes any step you get stuck on. Free, and nothing touches your real accounts.
Start the free lessonWhy does the AI reply come out wrong?
4. The model signs the email. A model asked to sign with a name and phone number can get them wrong, and "The Brookside Dental team" reads like a form letter. The lesson's prompt ends with a short closing line such as "Kind regards," and no name or signature, because the signature is added after the email.
5. Max Output Tokens too low. The cap includes the model's hidden reasoning tokens as well as the visible text, so a low setting can cut a reply short or leave it empty. The lesson uses 2000.
6. One long paragraph. Gmail's body is HTML and ignores plain line breaks. The prompt asks for each paragraph in <p> tags, and Body type is set to Raw HTML.
A seventh check belongs here too: the prompt puts the rules first and the mapped form answers last, so every run gets the same rules with a different patient. For a dental office the rules are: greet by first name, respond to the reason for visit, promise a call within one business day, and give no medical advice, prices or treatment promises.
Why is the signature missing even though the HTTP call works?
7. Mapping the wrong value. In Gmail's Body contents, map Result from the OpenAI module, type <br>, then map html from the HTTP module's Data. Mapping the whole Data bundle, or forgetting Parse response: Yes in the HTTP module, gives you raw text or nothing. Field mapping is precise: pick the exact field.
How do I keep the keys safe?
8. Keep the Signatoro key in Make's connection, never in the prompt or a note. Allowed service origins makes sure Make only sends it to signatoro.com. The OpenAI key lives in its own connection. Neither belongs in a shared blueprint: the tested blueprint ships with no key in it for exactly that reason.
How should I test before switching it on?
9. Save the scenario and click Run once with a new routine request waiting. Open the OpenAI module's bubble to read the input and Result, the HTTP module's bubble for Status Code 200, and then the sent email in Gmail. Repeat with several realistic requests and read every reply. If you'd rather check each email first, send the Result to Gmail Create a draft email instead of Send an email. The Zapier version uses draft replies by design; its own fixes are in Signatoro Zapier mistakes.
Key takeaways
- 401 means the
Bearerprefix is missing; 404 means no saved signature; Gmail 403 means missing send permission. - The AI writes the message and never signs it; Signatoro adds the signature after.
- Max Output Tokens 2000,
<p>tags and Raw HTML keep the reply whole and readable. - Map Result,
<br>, then html. - Keys stay in connections. The Make cheat sheet has every setting, and Signatoro is in the AI tools directory.
Frequently asked questions
- What does Status Code 200 mean in the HTTP module?
The call worked and Signatoro returned your signature. Anything else, check the 401 and 404 fixes above.
- Do I need a paid Signatoro plan?
No. The free plan includes the API, with 50 requests a month on 19 October 2026.
- Can I test without an OpenAI key?
The blueprint uses OpenAI Simple text prompt, which runs on Make's credits. With your own key, swap in Generate a response with the same prompt.
- Why is my reply empty?
Most often Max Output Tokens is too low, or your OpenAI account has no API credit. A ChatGPT subscription doesn't include API credit.
- Where are more answers?
See the Signatoro email signature FAQ.
