Hi @DUSKO SAVATOVIC
Thanks for visiting our forum, here we mainly focus on general issues about Outlook desktop client, so I'm afraid that we may know little about third party add-ins in Outlook.
As you have mentioned above, the MHA add-in works for Microsoft's account but not for other email account. I really did a lot of research about your issue but failed to found other similar add-in. However, as I know, the MHA add-in also have web version(https://mha.azurewebsites.net/) and we could use the web version to analyze all the message headers we have. Unfortunately, we need to manually copy the message header to the web for analysis which might be inconvenient for you, just as a workaround for you to refer.
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