We've just been migrated to Office365/OWA and still learning the ropes. We have a departmental account we want to share among our department. I've logged into the dept account in OWA, right-clicked the name of the account, went to Permissions, and given myself and my coworkers Owner level permissions (every right enabled). I've also tried doing the same for individual folders. These permissions have been active for a couple days now. There's also "Default (none)" and "Anonymous (none)", if those are somehow overriding our user-specific permissions.

However, trying to use "Open another mailbox" or trying to "Add shared folder" results in various errors that all seem to be lacking permission. It's the "Bad Request", or "You don't have permission to open this mailbox", etc. 

I don't have access to any server-admin level stuff, only just regular user abilities in the account I want to share and my own. 

Hi jeramie,

Thank you for your question.

We could run the following command to check if we have configured the full access permission for co-worker:

Get-MailboxPermission -Identity <mailbox> -User <delegate>

We suggest you run the following command on Exchange server:

Add-MailboxPermission -Identity <shared account> -User <co-worker account> -AccessRights FullAccess -InheritanceType all

we could refer to the following links:

https://technet.microsoft.com/en-us/library/jj919240(v=exchg.150).aspx

http://community.office365.com/en-us/f/148/t/167084.aspx

If there are any questions regarding this issue, please be free to let me know.

Best Regard,

Jim

Jeramie, permissions will only work if both the mailbox and the delegate are located in EO (or if both are on-prem). You should check with your admin stuff to clarify on this.