**Acceptance criteria**

Begin of the insertion1. **Invalid or Inaccessible Instance URL:** The URL you entered may be incorrect, inaccessible, or not using HTTPS.

End of the insertion * Begin of the insertionDisplayEnd of the insertion Begin of the deletion When a user inserts a correct URL forEnd of the deletion an Begin of the insertionerror message underEnd of the insertion Begin of the deletion instance onEnd of the deletion the Begin of the insertioninput field with the text `We can't connect with the instance URL. Please, check possible solutions here`

* `Here` should linkEnd of the insertion Begin of the deletion login page, but doesn't manageEnd of the deletion to Begin of the deletion proceed due toEnd of the deletion the Begin of the insertionLogin Troubleshooting documentation page

2. **OAuth Application Not Enabled:** The mobile app usesEnd of the insertion OAuth Begin of the insertion2.0End of the insertion for Begin of the insertionsecure authentication. IfEnd of the insertion the Begin of the insertionbuilt-in OAuth applications are not enabled in your instance, theEnd of the insertion app Begin of the insertioncannot log you in.

End of the insertion Begin of the deletion being disabled:

End of the deletion * Display an error message under the input field with the text `We can't Begin of the insertioncompleteEnd of the insertion Begin of the deletion connect withEnd of the deletion the Begin of the insertionOAuth Authentication.End of the insertion Begin of the deletion instance URL.End of the deletion Please, check possible solutions here` Begin of the insertion

* `Here` should link to the Login Troubleshooting documentation page

3. **Instance Not on Minimum Supported Version:** The OpenProject Mobile App requires your instance to be on OpenProject version 17.0.0 or later. If your instance is running an older version, OAuth authentication may be disabled by default.

* Display an error message under the input field with the text `Instance not on minimum supported version: OpenProject 17.0.0`

* No link to the documentation page, as we don't want the users to avoid updating OpenProject.

4. **Invalid SSL Certificate:** Your OpenProject instance must use a valid, signed SSL certificate (HTTPS). Self-signed certificates or expired certificates are not supported.

* Display an error message under the input field with the text `Secure connection failed. Untrusted certificate`

5. **Instance Using HTTP Instead of HTTPS:** The mobile app only supports secure connections via HTTPS.

* Display an error message under the input field with the text `Secure connection failed. Untrusted certificate`

6. **Firewall or Network Restrictions:** Corporate or restricted networks may block outbound requests to your OpenProject instance or authentication endpoints.

* Display an error message under the input field with the text `Login time out. Check your network`


End of the insertion Begin of the deletion


End of the deletion **Technical notes**

* <br>


**Permissions and visibility considerations**

* Everyone


**Out of scope**

* <br>