Dear Colleagues, I come to you with a simple question and I trough that you can help me faster than any other documentation. We have an ISA Server 2004 connected to our main domain, with only one interface and used purely for caching. The settings are all ok, everything works all right. In this enviroments we add another server with intentions to have 2 servers in array. We would like to make a fail over at DNS level with same record and two IP. After this array created successfully, there is one error on each ISA machine: Description: ISA Server cannot connect to xxx.xxx.xxx.xxx proxy server because the server requires authentication, either when chaining or for intra-array communication. However authentication failed because the specified credentials were incorrect. Check authentication credentials and try again. While XXX.XXX.XXX.XXX is the address of OTHER server. In this spirit I reach the conclusion that there is a problem in INTRA ARRAY communication. The second server it have CARP Load factor to 1 and the old server have CARP Load factor to 100. In this enviroments .... When an end user connects to the second server it got the following error: * Error Code: 502 Proxy Error. Logon failure: unknown user name or bad password. (1326) * IP Address: server isa old * Date: 2/6/2007 7:18:37 AM * Server: server isa new * Source: proxy I can only conclude that Intra-Array authentification is the problem. If you can provide me a fast advice I would appreciate very much. Yours sincerely, Bogdan Florin CEO InterNetCon - Satellite Internet Services www.internetcon.ro <http://www.internetcon.ro> www.powersat.ro <http://www.powersat.ro> Phone: +40-264-452383 Cell: +40-740-074031 Cell: +40-788-074031 Fax: +40-264-452207 All mail to and from this domain is GFI-scanned.