You have to check the external account configuration.
On Campaign side:
Product Context: it can be left as blank (or dma_campaign) if Admin Console – Campaign Product Profiles looks like “CampaignV6 - <Experience Cloud Tenant> - <admin, etc...>” , otherwise, in case of CampaignV7 configuration, it should be dma_campaign_classic
The Tenant should point to the “PRODUCTION” Experience Cloud Tenant
The Association Mask MUST reflect the Product Profiles in Admin Console – Campaign. So, for example, if we have CampaignV6 – YXZ – admin, the Association Mask must be CampaignV6 – YXZ – (.*), it is a simple regex
IMS must be configured (and you have to access the instance with this user) in order to create the Lists for saving the shared audiences.
Everytime you modify a parameter in the external account, the web process should be restarted.
On Admin Console side:
The user should be assigned to the Audience Library – Product Profiles “Audience Library” – Users
The user should be assigned to the Campaign PROD environment – Desired Product Profile (i.e. CampaignV6 – YXZ – admin) -- Users