Hello @felipeguerra,
I hope you are doing well, and thanks for reaching out. We're sorry for the trouble you had.
The issue is likely due to how Acrobat updates and uses its local trusted certificate list, especially if that list hasn’t been refreshed or if AATL updates are disabled.
Suggestions:
Open Acrobat/Reader’s Preferences. On Windows, go to Menu> Preferences. On macOS, go to the Acrobat > Preferences menu.
In the Preferences dialog, select the Trust Manager category from the list on the left.
Under Automatic Adobe Approved Trust List (AATL) updates, enable the checkbox “Load trusted certificates from an Adobe AATL server”
Click the “Update Now” button in the Trust Manager section. If prompted to confirm, click “Yes” or “OK” to allow Acrobat/Reader to download the latest Adobe trust list. This fetches the most up-to-date list of Adobe-trusted root certificates (including IdenTrust’s root).
After the update, click OK to close Preferences, then re-open the signed PDF. The digital signature should now validate automatically – you should see the signature status as valid (with a blue ribbon or green checkmark, indicating the signature is trusted by the updated list).
To learn more, please check this Adobe article: Manage trusted identities.
Also, please ensure you/users have the latest version of Acrobat installed on the machine: Version: 26.001.21563. Planned update, May 18, 2026. Check for any pending updates by navigating to Menu > Help> Check for Updates. Install the updates, restart the app and the machine, and try again.
Let us know how it goes.
Regards,
Anand Sri.
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