1. Your policy settings may be so, change the settings

2. For On-Prem Exchange environment: This is an issue that must be solved in Microsoft side. You should take the actions in the link below. It should work afterwards. You don’t have to re-create the manifest file.

https://learn.microsoft.com/en-us/office/dev/add-ins/outlook/outlook-on-send-addins?tabs=classic#install-outlook-add-ins-that-use-on-send

Open

There may be several reasons.

1. Is the GEODI server running?

2. Before creating the manifest file, make sure the GEODI URL address in the UI is correct. Otherwise, repeat the installation.

3. Microsoft OWA servers must see the GEODI server. If you are using Exchange Online, the GEODI address must be public.

4. SSL must have been defined for the GEODI address. Be sure that SSL is defined and that it is not expired.

1. Is the GEODI server running?

2. Is the project that is used to create the manifest file still active? If not, revert the project or re-create it. In case of re-creation, the manifest process must be repeated.

3. Is the TokenUser and its password still valid? If not, the manifest process must be repeated.

1. No, all changes applied automatically.

2. Manifest reload is required in cases like GEODI Url or Tokenuser changes.

1. Yes, It can be done for testing or other requirements. Create multiple projects and manifest files for each.