Why SMSBackup+ won't feed the most recent backup to my new phone?

[Android Central Question]

I just purchased a new phone (One+ 6T), before shutting down my old phone (Huawei Honor 8) for good I backed up all my text messages using SMSBackup+.
The app on both phones connects to my gmail account.
However, the old phone shows that the most recent backup was done today (January 2019), while the new phone on the same app shows the most recent backup as September 2018.
Ideally I want to transfer all my old text to the new phone (it's all business and I cannot lose the threads of those conversations)
Do you have any suggestion?

 

[Rukbat]

1. Make sure that everything in your Google account on the 6T is set to sync.

2. Look at the SMS Backup+ file in a text editor (one that can handle Linux line ending). It's not exactly user-friendly, but it is human-readable. See if anything is obviously wrong. Post the part you think is wrong here. (It's an xml file, and I read those like I read dime novels - so if there's a character that's out of place, or wrong, I'll be able to give you the proper text to replace it with.)