Institutional subscribers hitting pay wall

Our institutional subscriber users are hitting the pay wall when trying to access articles in our journals through their institution. The institutional subscription is set up correctly (IP ranges etc) and the subscription is current and active. Nothing appears to be wrong on our end, but this is happening with multiplie institutions in multiple countries, which suggests the issue is on our end and not theirs.

I am wondering if anyone else has had this issue and what might be causing it?

Version: OJS

Our problem persists and we can find no cause or solution. Can anyone recommend a company or individual that can provide high-level technical support for us to fix this problem?