Unable to open shared mailbox in OWA

Hi,

I am trying to open a shared mailbox via OWA, but I get an error message "Something went wrong"

cId: 794BB9E785A14F029964736E908D456C
app: Mail
ebe: SYCPR01MB3758
et: ServerError
esrc: MasterPage
ts: 11/21/2019 10:04:19 PM

I have multiple users that have FullAccess to the shared mailbox.

All users can see the mailbox in their Outloo client (O365 ProPlus 1808)

I also have access to other Shared Mailboxes and I can open them without any issue.

I have removed permossions and re-added them without any luck.

Does anyone know what I else I can try?