The issue have several symptoms and there are several variations known.
Known symptoms list:
1) The issue occurs when trying to reauthenticate after refresh token expiration.
Default refresh token lifetime is 90 days and after that MS Graph API Image Import Profile may stop working with corresponding error. To resolve it, reauthentication in Image Import Profile is required.
2) Clicking "Sign In" in existing MS Graph API Image Import Profile and clicking the generated link ends with "This site can't be reached" at go.abbyy.com... redirect step.
3) Clicking "Sign In" in existing MS Graph API Image Import Profile and clicking the generated link ends with "Access denied" even if provided credentials are correct.
Previously generated permission is reused but it is no more applicable, and a new prompt for permissions is blocked by an existing one.
Permissions to FlexiCapture 12 in the Azure account should be revoked and granted again:
1. Revoke existing permission for FlexiCapture 12 in the client's Azure account (at http://myapps.microsoft.com/). This procedure should be performed on behalf of the user who will then create a new permissions grant.
2. Click "Sign In" in the MS Graph API Image Import Profile settings.
3. Authenticate to your mailbox.
4. Permissions prompt window will appear:
5. Accept the permissions grant.