Client Outlook MAC 2016

I have a problem with OUTLOOK MAC 2016 When I say Mac Outlook Client doesn't work means all of our Mac clients are getting prompt in the MAC Outlook - Error shows Unknown user name or bad password.the LTM version that I have is 11.4.1 . the error message that I have to sniff it

10 0.0054 (0.0007)  C>SV3.3(560)  application_data
---------------------------------------------------------------
POST /ews/exchange.asmx HTTP/1.1
Host: mailXXX.XXXX.XX
Content-Type: text/xml; charset=utf-8
Cookie: BIGipServer~exchange~exchange2010.app~exchange2010_combined_vs_owa_pool=2752124170.47873.0000; exchangecookie=xxxxxxxxxxxxxxxxxxxxxxx
Connection: keep-alive
Authorization: NTLM XXXXXXXXXXXXXXXXXXXXXXXXXX
Accept: */*
User-Agent: Mac+OS+X/10.11.5 (15F34) CalendarAgent/361.2
Content-Length: 0
Accept-Language: fr-fr
Accept-Encoding: gzip, deflate
    2 11 0.0110 (0.0055)  S>CV3.3(592)  application_data
---------------------------------------------------------------
HTTP/1.1 401 Unauthorized
Server: Microsoft-IIS/7.5
WWW-Authenticate: NTLM xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
WWW-Authenticate: Negotiate
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Date: Wed, 15 Jun 2016 14:04:10 GMT
Content-Length: 0

thanks