Hello,
I found a solution to my problem.
i delete my account (pop3) and all mails, on my phone ( remember my mails are backup on my computer).
I set new imap account on my phone (which was empty, as my mails were downloaded on my computer).
i set new imap account on my computer.
On my computeur, i copy my emails (backup) to the new Imap account.
Synchronise my phone....and all mails are back on it.
As my account configuration is now "imap" on my phone..no more problem to change phone.
AquaMail is great app.
Thanks.
Denis