Whenever i create a new customer almost all of my users (900) get a message:

Outlook was redirected to the server <url> to get new settings for your account

<public folder mailbox> Do you want to allow this server to configure your settings?

And some get the message that they need to login for the new public folder....

That's very odd behavior.

Do all of your users have the public folder fix?

so 1 main public folder per organization, and each user has their organization's main public folder as their default?

As Exchange behaves odd and random without that in place.

I don't know exactly what you mean.

Currently we have 1 public folder mailbox, when i create a new customer and only when they want to use public folders (old way, not via solidcp) it will create a folder in that mailbox, setup the rights and off they go.

I came accross this Topic:  https://solidcp.com/forum/question/public-folder-creating-error-in-autodiscover/

Same issue, i try and used the PFFix, if i do that it recreates the public folder mailbox.

When i than look at the rights, i see no more anonymous.

It gets the same rights as i do with my own script, so i guess this is ok now.

Creating a subdir also is ok, but if i than alter the permissions via solidcp i get a error:

Error updating public folder general settings. See audit log for more details.

System.Web.Services.Protocols.SoapException: Server was unable to process request. ---> System.Exception: Error executing 'UPDATE_PUBLIC_FOLDER_GENERAL' task on '' EXCHANGE ---> System.Web.Services.Protocols.SoapException: Server was unable to process request. ---> Object reference not set to an instance of an object. at System.Web.Services.Protocols.SoapHttpClientProtocol.ReadResponse(SoapClientMessage message, WebResponse response, Stream responseStream, Boolean asyncCall) at System.Web.Services.Protocols.SoapHttpClientProtocol.Invoke(String methodName, Object[] parameters) at SolidCP.EnterpriseServer.ExchangeServerController.SetPublicFolderGeneralSettings(Int32 itemId, Int32 accountId, String newName, Boolean hideAddressBook, ExchangeAccount[] accounts) --- End of inner exception stack trace --- at SolidCP.EnterpriseServer.ExchangeServerController.SetPublicFolderGeneralSettings(Int32 itemId, Int32 accountId, String newName, Boolean hideAddressBook, ExchangeAccount[] accounts) at SolidCP.EnterpriseServer.esExchangeServer.SetPublicFolderGeneralSettings(Int32 itemId, Int32 accountId, String newName, Boolean hideAddressBook, ExchangeAccount[] accounts) --- End of inner exception stack trace ---

Hmm, that error is very generic

do you have any further warnings or errors in your event viewer on the Exchange server ? as it should have a bit more information as to where it falls over.