Message had syntax that was not valid

We are using Lotus Notes 6.5 and when a user replies to a mail recevied from Exchange Server (external domain),  User is getting a NDR with "Message had syntax that was not valid".   I could not find any solution for this or could not understand root cause.  Can someone help in resolving this.
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Sjef BosmanGroupware ConsultantCommented:
Is this happening with any external Exchange server? Does it happen with ALL mails replied to? And for ALL users?

Other pages on this particular error are rare, and often very similar. Most likely culprit: one of the mail addresses used isn't correct (RFC821/822 ??).
     Hi there smart_expert,,,

First of all,,, did you search for an appropriate Fix for this problem .????

Second of all,,, I wonder if you though about any upgrade to the loastest versions of LN e.g. 8.5 as far as I know no such a similar problems happen with this version .Moreover, LN6.5 will be outdated and there will be no support for it by IBM .

Best Wishes


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