How do I apply folder settings to all folders (or subfolders)?

[Patrick Bateman]

I have an IMAP account with a relatively complex folder structure (say, 100 folders, many of them sub-folders of others).

I have a constant issue with K-9 mail where I find that emails in certain folders aren't showing up in the unified inbox.  Almost always, this turns out to be because that particular folder lacks some setting (folder class, "unify" ticked, etc).

How can I apply identical settings across all folders?  E.g. set all folders to first class and unify?  It's almost impossible to reliably do this for 100 separate folders on a phone.

[Pasquale Degli Esposti]

Please, help me. I've tried all setting.
I don't understand why.
The hw is a tablet Huawei mod. T1-A21L
There is a sim data unlock and not operative.
But I think these thinks aren't interesting.
Thank you.
For me there is no alternative to K9 mail for ancient people for its simplicity.
Thank you for your attention.

[Gunter Königsmann]

What seems to be the problem? What are the symptoms of the problem? And
- just a wild guess at the next question: Do you have two-factor
authentification enabled in your google account?

[Pasquale Degli Esposti]

Thank you very much Mr. Königsmann,
With the change of authentication of less secure apps for Gmail, everything went well.
Thanks again.
Giuseppe Deledda.

--
Inviato dal mio dispositivo Android con K-9 Mail. Perdonate la brevità.