Users over WAN can't connect to outlook but LAN and VPN works. we have port 25 open.  What other ports need to be ope

Hi Alex,

Thank you for your question.

First, we could make sure that we have registered MX and Mail record in ISP. Then check if we could configure profile manually.

Are there any errors when we configure outlook profile?

If we could configure profile manually, we could make sure we have configured autodiscover on Exchange 2013 by the following link:

https://technet.microsoft.com/en-us/library/bb124251(v=exchg.150).aspx

By default, outlook anywhere has been enabled on Exchange 2013, we could install a valid SSL certificate on CAS server. the more details we could refer to the following link:

https://technet.microsoft.com/en-us/library/bb123741(v=exchg.150).aspx

If the issue persist, we could use the following link to test connectivity. If there are any errors, please post errors to ibsexc@microsoft.com for our troubleshooting.

https://testconnectivity.microsoft.com/

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

Best Regard,

Jim

Try 443

https://technet.microsoft.com/en-us/library/bb123741%28v=exchg.150%29.aspx?f=255&MSPPError=-2147217396

Hi,

Are there any updates?

Best Regard,

Jim