Hello people, I need some expert advice. I am going to rip my hair out here.
I have mailbox A that needs to have a few people be able to send from it.
I have exchange 2010
I gave the users the Send As permission and the Full Access permission
I also went into ADUC and in the security tab added the users and gave them full access to the user whos mailbox I want them to be able to send from (because for whatever reason from the EMC it would add the user in the security tab in ADUC but not give them any permissions...allow and deny wouldnt be checked off)

Here is the kicker. 
When I try to send an email from email1@domain.com from user1@domain.com <--the user who should have access to this mailbox from Outlook it doesn't work
When I try to OWA it works.


I read that the OAB files might need to be updated so I downloaded the Address book from Outlook...nothing...I even deleted the OAB files from the profile...nothing

I went as far as to delete the mail profile completely...nothing...

I am out of ideas I know I am missing something but what....

I cant understand how it works from OWA but not Outlook


Edit: This may or may not mean anything but when I get the bounceback in my mailbox I get this error

You can't send a message on behalf of this user unless you have permission to do so. Please make sure you're sending on behalf of the correct sender, or request the necessary permission. If the problem continues, please contact your helpdesk.


It is FROM: MICROSOFT OUTLOOK and not FROM: email1@domain.com

Hello,

Have you tried restarting 'Microsoft Exchange Information Store service' ?

Check for any replication issues in DC event logs

Most likely you are using an older/outdated entry for the sender. Start composing a new message, press the From button, press the little 'x' to remove any stored entry then select Other e-mail address, press the From button and select the address directly from the GAL (do not type/use the autocomplete entry). Back on the "Send from other e-mail address" dialog, make sure that under "Send using" your account is selected (this will only be visible if you have multiple accounts added in Outlook).

Most likely you are using an older/outdated entry for the sender. Start composing a new message, press the From button, press the little 'x' to remove any stored entry then select Other e-mail address, press the From button and select the address directly from the GAL (do not type/use the autocomplete entry). Back on the "Send from other e-mail address" dialog, make sure that under "Send using" your account is selected (this will only be visible if you have multiple accounts added in Outlook).

• Proposed as answer by Niko.ChengMicrosoft contingent staff, Moderator 23 hours 55 minutes ago

Most likely you are using an older/outdated entry for the sender. Start composing a new message, press the From button, press the little 'x' to remove any stored entry then select Other e-mail address, press the From button and select the address directly from the GAL (do not type/use the autocomplete entry). Back on the "Send from other e-mail address" dialog, make sure that under "Send using" your account is selected (this will only be visible if you have multiple accounts added in Outlook).

• Proposed as answer by Niko.ChengMicrosoft contingent staff, Moderator Monday, May 11, 2015 7:30 AM

Hi Rigel,

Have you tried the suggestions above? How about the result ?

Best regards,

Try to select the "from" account selecting it from the global address list instead of typing it.