topic Re: From address doesn't meet the authentication requirements defined for the sender in Email

Error connection dropped by imap server

Stanleh — Thu, 02 Oct 2025 16:24:32 GMT

So I am trying to check the inbox of a plusnet email it's plus.com variant and outlook isn't downloading the emails but neither is emclient, so I logged in via the plusnet wrbmail and I get this error message "Error connection dropped by imap server"
Their second email address works fine via outlook and webmail.

Re: From address doesn't meet the authentication requirements defined for the sender

Stanleh — Thu, 02 Oct 2025 15:56:04 GMT

Ok so things didn't go exactly to plan, I changed the settings on their two email accounts, one works perfectly but the other one won't display incoming emails
It shows the notification for new message in the bottom right but nothing shows in the inbox and if I click the notification it says "the message you specified cannot be found"

It does this with outlook on two different machines and the emsclient doesn't download the emails either.

If I try and log into their webmail client it says "error connection dropped by imap server"

Re: From address doesn't meet the authentication requirements defined for the sender

PhilipHeyes — Thu, 02 Oct 2025 17:47:20 GMT

You changed what email settings, from what to what & for what purpose ?

The a/c that is not working in Webmail due to an IMAP server issue, that needs to be resolved first
before expending more time on email clients like Outlook etc.

Re: From address doesn't meet the authentication requirements defined for the sender

Townman — Thu, 02 Oct 2025 17:48:58 GMT

@Stanleh wrote:
Ok so things didn't go exactly to plan, I changed the settings on their two email accounts, one works perfectly but the other one won't display incoming emails

That hints at the oddity which arises sometimes where one needs to specify the IMAP root folder as inbox

There is also the possibility that there is a very big email queued for synching which is causing the connection to time out. Set the server connection timeout to 2 minutes.

Re: From address doesn't meet the authentication requirements defined for the sender

Stanleh — Thu, 02 Oct 2025 17:51:15 GMT

So I changed the outgoing mail to starttls and port 587, in outlook this worked fine as I sent and received test emails then I get a call today they aren't able to get emails, so I change the security settings and port back to what it was and still no luck.
So then I think to login to their webmail but it won't login, it gives me the error message I mentioned above about imap, surely it it was the fault of the outlook settings I changed then their webmail would be fine to log into?

Re: From address doesn't meet the authentication requirements defined for the sender

Townman — Thu, 02 Oct 2025 17:55:13 GMT

Anything done on the IMAP client has nothing to do with logging in via webmail.

Get the webmail login working - be clear about the brand (check the provider option box), user ID being used and the password.

Re: From address doesn't meet the authentication requirements defined for the sender

Stanleh — Thu, 02 Oct 2025 18:10:47 GMT

Thanks for the quick reply, their details are saved so correct as far as I can tell, it's set to log in as plusnet and their secondary email works in both webmail and outlook

So I just tested sending an email via outlook and it sends fine, it's just receiving (so imap) that seems broken
I have changed root folder path to Inbox but no luck with that

If it was the wrong password in webmail would it give the imap error I mentioned above?

Re: From address doesn't meet the authentication requirements defined for the sender

Townman — Thu, 02 Oct 2025 19:43:58 GMT

Can you log into each account using webmail?

Webmail can experience connection issues if there’s a massive mailbox or a large mail item.

Re: From address doesn't meet the authentication requirements defined for the sender

Stanleh — Thu, 02 Oct 2025 19:49:14 GMT

Hi, sorry about the delay
They got home and gave me the correct details and I was able to login to both of the webmails, however the one I am having problems on wasn't showing any new emails, the last one was at 12:47 yesterday which coincides with the last email they were able to download via outlook but I know they have other emails that should be showing as we have sent test emails from multiple accounts.

Re: From address doesn't meet the authentication requirements defined for the sender

Townman — Thu, 02 Oct 2025 20:13:48 GMT

How have they configured outlook? POP3 or IMAP?

Re: From address doesn't meet the authentication requirements defined for the sender

Stanleh — Thu, 02 Oct 2025 20:18:20 GMT

Imap and it was working fine until yesterday

Re: From address doesn't meet the authentication requirements defined for the sender

Stanleh — Thu, 02 Oct 2025 20:41:29 GMT

Any idea why the new emails aren't showing up in the webmail either?

Re: From address doesn't meet the authentication requirements defined for the sender

PhilipHeyes — Fri, 03 Oct 2025 06:18:13 GMT

"wasn't showing any new emails" for a Web Mail client using IMAP this can mean the new emails are not there to see.

Could spam settings or mailbox being full be an issue ? What is in the SPAM / Junk folders ?

Re: From address doesn't meet the authentication requirements defined for the sender

Townman — Fri, 03 Oct 2025 07:36:09 GMT

A plus.com mailbox does not stop receiving emails when full.

Re: From address doesn't meet the authentication requirements defined for the sender

Stanleh — Fri, 03 Oct 2025 07:59:14 GMT

I think Philip nailed it, I deleted stuff out of their deleted folder (I didn't want to randomly delete their emails without checking) and now they are able to receive my test emails but it seems like anything sent in the last 48 hours has been lost.

Re: From address doesn't meet the authentication requirements defined for the sender

Townman — Fri, 03 Oct 2025 08:18:43 GMT

Something is not clear / quite right here.

Plus.com / Force9 / FreeOnline email services on the Plusnet platform do not have a hard quota and do not stop receiving more email when the 1GB quota is full. On the Greenby platform the 2GB quota is hard and when full new email will not be received. No accounts on these brands have moved.

On the Plusnet platform all the other brands have a 250MB hard quota.

@Stanleh wrote:
So I am trying to check the inbox of a plusnet email it's plus.com variant …

If that statement was correct then something does not add up … and certainly for me directed away from a full mailbox being the cause here.

Further, deleted items folders are culled every week by PlusNET’s house keeping for the 3 brands above.

Re: From address doesn't meet the authentication requirements defined for the sender

Stanleh — Fri, 03 Oct 2025 08:34:23 GMT

Ok so their email is user@user.plus.com, they told me they normally get warning emails when their account is full but nothing this time.

However I deleted about 6 to 10 emails from their deleted folder and they were suddenly able to receive my incoming test emails, however none of the emails from the last 48 hours have arrived, are they lost for good?

The other strange thing is, I emptied the trash can last night but when I looked again this morning some of those emails were back in the trash as though they had not been permanently deleted.

If you want I can boot up my computer and check their web account to see how much space was used but I believe it was somewhere around 600mb (it was late and I was extremely tired last night so I don't remember for sure)

Re: From address doesn't meet the authentication requirements defined for the sender

Stanleh — Fri, 03 Oct 2025 09:00:39 GMT

So I just checked the folder size and it was roughly 470mb and I didn't delete more than 10mb last night, could it have been plusnet had an issue with their servers and it got fixed and it was just a coincidence that I had emptied the trash at roughly the same time.

She really wants to know if she can get back any emails sent in the last 48 hours, they are now getting new emails (they just got one about a parcel being delivered) but still nothing from the last 48 hours.

Again thanks for all the help so far mate

Edit

Ok I just spoke to Plusnet and they said because their account has two emails the file size limit is spread across both accounts, although I don't have access to his email, he was still able to receive emails so I am not sure that theory makes sense.