Why can I only post to one Twitter account at a time in Social Publisher?
Due to a change of policy by Twitter made in February 2018, you can no longer post the same content to more than one Twitter account. This is as part of Twitter's efforts to reduce spam on their service.
The updated rules for third party apps such as Aiir state:
Do not (and do not allow your users to) simultaneously post identical or substantially similar content to multiple accounts. For example, your service should not permit a user to select several accounts they control from which to publish a given Tweet.
Because of this, we have removed the ability to post to multiple Twitter accounts at the same time.
If you need to share an identical message across multiple accounts, Twitter recommends:
As an alternative to posting identical content, you can Retweet content from one account from the other accounts you wish to share that post from. This should only be done from a small number of distinct accounts that you directly control. Please note that bulk, aggressive, or very high-volume automated Retweeting is not permitted under the Automation Rules, and may be subject to enforcement actions.
We have contacted representatives from Twitter to discuss whether the circumstances of radio stations networking content across multiple brands could be seen as an exception however were told this would not be the case.
You can find out more about Twitter's policy on their development blog.