POP3 has, for all practical intents and purposes, been a dead access protocol for years now.
I actually wish that e-mail client coders had intentionally phased out support for it. It is a horrible anachronism that has caused so many cases of heartache that would have been entirely avoidable had IMAP been being used instead.
I have yet to see any e-mail service provider permanently lose messages on their servers under their care. Professional data centers have backup protocols in place that we home and small business users could never have even if we wanted them. They're not going to lose this stuff.
Once POP messages are downloaded, and deleted from the server (which is the default behavior, and will eventually happen even if you put in a delete deferment) they're you're problem. And given how frequently many home and small business users have no backup protocol of their own in place (which is jaw-dropping at this stage of the game of personal computers having been around, and failing, for decades) I've seen years of email go up in proverbial smoke.
I will not even set up email using POP unless the service provider (and there are precious few) only supports POP access. And in the very rare occasion where that's the case, my first recommendation, made very strongly, is that a new email service provider be found ASAP, even if the original address is maintained and messages forwarded from it.
Say NO (abso-friggin'-lutely NO!) to POP!!