Hello
First of all, apologies for my language, English is not my primary language and i still learning 
2 days ago after receiving AirMail growing price email i decide to move to another, on my PC i was using thunderbird, i have also iphone 16 pro max and ipad pro where i had a AirMail app.
I decide to move from thunderbird to em Client on my PC.
On PC everything went smooth, without any problems with notifications etc. I noticed that i can easily move accounts from Thunderbird to emClient which was very nice :))
Then i found i can also export emClient settings etc onto mobile app on my iPhone and iPad.
I started with iPad where i used QRCode from PC app and exported everything onto iPad. Everything works fine, notifications, push etc..
Then using same method i moved data from PC to iPhone, and start having problems, no notifications about new emails, no push, only could see emails when i enter emClient app on iPhone and had to wait couple of minutes until they download, was very frustrating I read the entire forum.. (i’ve seen thread where someone even reinstalled iOS - that was too crazy for me to test - do not have that time to restore everything later)
I have removed app and tried to synchronize again, same story..
btw im hard user - i’m using from 10 to 15 mail accounts o.O
next episode was that i again removed application and tried manually add accounts, and it was ok, but im lazy ^^ and want do it automatically - especially that i spend lots of time on my PC to set emClient and all inboxes, signatures etc. so what i did?
I have again reinstalled application, by using QR code i’m imported all accounts, settings etc.. still no push and notifications (even on apple watch), so this time i have exported (FROM IPHONE!) all settings to the FILE, then i removed again emClient and install it again (I’ve increased your appstore download count a bit xD)
after installation i have just imported that file and voilà ! everything starts working, notifications, push, apple watch notifications, now im receiving notification straight away, not need to open emClient, no lags or slow downloads.
However as i mentioned above on iPad it was working fine - no issues, no problems with push, only on iPhone (using latest iOS).
I think iOS app has some problems with importing settings via QR from PC.
I decide to describe and leave this here for other people who might have same issue, this is worth to try before they skip to other application.