API token is invalid error

[chiaraga00]

Hello, I'm trying to connect Notero to my Notion but I keep getting "API token is invalid" in Zotero.
I tried both to create a new template or to connect to a duplicated template from the Notero installing page (i.e., Notero Advanced) but in both cases it connects/creates the template but it stays blank (no papers, nothing).
I also tried copied the token instead of just opening the app, but same result.
I also tried disinstalling and re-installing Zotero and the Notero plugin.
The sync options are activated in Zotero.
If I click on the ... button in Notion there is the authorized connection to Notero.
I also get the API token not valid message when I normally upload a new paper in Zotero.
What am I missing?
Thank you in advance for any help!

[nabusse]

I also have been getting the same error.. I followed the pipeline exactly as shown.
In an older issue, they said that there could be some additional spaces accidentally copied, but that is not the case for me

[dvanoni]

Hi @chiaraga00 and @nabusse, thanks for reaching out. Some other folks have also run into this issue, and I previously suggested some steps to try to resolve the issue that worked for them.

You can also try those steps to see if they work for you, though I'd love to get more details from you as try them to help me debug this issue. Ideally I can prevent it from happening to more folks!

I'm hoping to determine whether this issue is more on the Notion side or within Notero/Zotero. In my original post I suggested two steps:

• Remove connection in Notion
• Remove Notion credentials from Zotero

I'd like to test these one at a time to hopefully determine which actually helps. Here's what I'd like you to try if you don't mind:

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Remove connection in Notion

1. In Notion, open the settings screen, navigate to Connections, and then disconnect Notero from your account.

   

2. In Zotero, open the Notero preferences, try the "Connect to Notion" process, and then take a screenshot of the Error Console.

   CleanShot.2025-09-24.at.22.50.01.mp4

---

If the above does not solve the issue:

Remove Notion credentials from Zotero

1. In Zotero, open the Error Console, paste the following command into the prompt at the bottom, and then hit Return to run it.

   Zotero.Notero.notionAuthManager.removeAllConnections()

2. Take a screenshot of the Error Console, which should hopefully look something like this:

   

3. Try the "Connect to Notion" process again, and then take another screenshot of the Error Console.

---

I really appreciate your help with debugging this!

[nabusse]

thanks so much! the debugging step: "Remove Notion credentials from Zotero
In Zotero, open the Error Console, paste the following command into the prompt at the bottom, and then hit Return to run it" and then reconnecting worked wonders, now it is all syncing! thanks you soooo much!!

[dvanoni]

Thanks for the input, @nabusse!

I still don't know what's causing the error in the first place, but I think I can at least improve the reconnection flow in Notero when the error arises. I'm going to keep this issue open to track work on it.