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Acumatica 2025 R1: Cannot reuse the same External Application for multiple Email Accounts

  • March 18, 2026
  • 3 replies
  • 18 views
thisarab07

Hi everyone,

I am currently setting up multiple Email Accounts (Exchange Online SMTP/IMAP/POP3) for a client in Acumatica 2025 R1.

I have noticed a significant change in how the system handles External Applications (SM206540). When I create an External Application and link it to my first Email Account, that specific External Application completely disappears from the selector when I try to configure the second Email Account.

It appears the system is now enforcing a strict 1:1 relationship between an Email Account and an External Application. In previous versions, it was standard practice to use a single Azure AD App Registration (i.e., one External Application record in Acumatica) to authenticate multiple mailboxes under the same tenant.

My Questions:

  1. Is this strict 1:1 mapping an intended security design change in 2025 R1, or is it a known bug?

  2. If this is the intended behavior, what is the recommended best practice for setting up 20+ email accounts? Creating 20 separate External Applications in Acumatica seems highly redundant. Is there a configuration to bypass this and allow a 1-to-many relationship?

Any insights would be greatly appreciated. Thanks!

3 replies

A
Captain II
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  • aiwan
  • Captain II
  • March 18, 2026

​@thisarab07 

 

I had the same experience in 24R2, I thought this was by design.

In my opinion it seems sensible, 1 account gets one token so if the external application is somehow hijacked, it only affects one email account.

Aleks
    KrunalDoshi
    Jr Varsity II
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    • KrunalDoshi
    • Jr Varsity II
    • March 18, 2026

    Hi ​@thisarab07,

    You can configure your external application (SM301000) with Type = OAuth2.0 and then configure your email accounts (SM204002) with Authentication Method as OAuth2.0.

    Hopefully this helps.

     

     

    Krunal D - Acumatica Developer | www.linkedin.com/in/onlyleader | https://krunaldoshi.com/
      Graeme Laughton-Mutu
      Semi-Pro II
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      I wasn’t aware of previous many-to-one using a single Acumatica External Application, we have always created an External Application per Email Account in Acumatica.

      The External Applications can all use the same O365 key, so at least there can be a many-to-one relationship in that sense, without needing to create O365 applications/keys per email account.

      Graeme Laughton-Mutu | Focus Technology Group (NZ)
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