Outlook Android App error occurred during authentication. Please try again later.

Step 1 - I had before posting on this forum, and I can confirm that I got the same error on more than one phone. I cleared the app cache on the phone and tested it, same error. Then I removed the app from the phone and reinstalled it, same error. Finally, I entered the advanced boot mode of Android and cleared the app cache, same problem after reinstall again.

Step 2 - All Exchange and Active Directory servers have their SPNs correct. Here is an example:

https://learn-attachment.microsoft.com/api/attachments/7ed066d9-ce8c-4dc7-8ac2-9f105fa2d49b?platform=QnA

Step 3 - I don't use modern authentication on-premises with OAuth or any third-party authentication. I continue to use the same basic on-premises authentication model in both on-premises Exchange forests.
https://learn-attachment.microsoft.com/api/attachments/f5afd0f4-1f96-40f3-a0e6-d63b49e520bd?platform=QnA

Step 4 - They all point to the same URL.

https://learn-attachment.microsoft.com/api/attachments/8587d99f-4725-45e5-bfb1-43ae475f93ee?platform=QnA

Additional steps 1 - Another test I did was, I prepared the account via Prepare-MoveRequest.ps1, ran ADMT, merged the password, didn't copy the SidHistory, moved the mailbox to the new forest, and tried to reconfigure it in the app, but the same error occurred.

Additional steps 2 - I have already tried renaming the UPN and reverting to the original UPN, renaming the SamAccountName and reverting to the original, and even changing the UPN to another one.

Is there any workaround I can do on the Exchange server side or on the user's app to clear any issues and allow using the email in the username field? For accounts created in the destination environment, it has always been like this. Workaround to configure post-migrated accounts:

Email address: login@domain

Password: User's forest password

Server: FQDN of the NEW on-premises Exchange server

Domain: Empty

User Name: login@domain (Expected, objective)

User Name: DOMAIN\SamAccountName (Workaround, bad config)

Note: If I change the user's UPN attribute domain in Active Directory, for example: I rename from email address removed for privacy reasons to email address removed for privacy reasons in the UPN attribute and in the "Username" field I change email address removed for privacy reasons to the email email address removed for privacy reasons, it works. There is something exclusively with this Outlook Mobile App that does not handle the UPN correctly after migration.