8 steps to migrate smoothly from PN/Greenby email to another email provider (example based on Gmail)

[#1]

Background

I look after my father in laws plus-net account for him. The forced migration to Greenby has accelerated a plan to migrate him to Gmail for email. I used Chat GPT to help work out the best way to do this, and then asked it to summarise the process - as provided below. 

If you also want to do the same or similar, it should work for migration to any email provider which can import emails from another account via POP3. I hope you find it useful.

Summary

• All existing/historic mail is preserved

• New mail is delivered immediately

• Greenby remains available as a fallback

• Gmail becomes the primary mailbox

Why I did this

My father-in-law’s Plusnet email address was receiving an unmanageable volume of spam.
After the migration to Greenby, I’d hoped the spam filtering would improve, but in practice it didn’t make a significant difference. I don't know if Greenby is worse than plus net - but it is certainly no better - and nowhere near good enough.

As Greenby is only provided free for two years, we decided to move to Gmail for its far better spam filtering, while using the Greenby service as a temporary bridge to ensure a smooth, low-risk transition with no loss of email.

This approach allows plenty of time to migrate gradually and verify that everything is working correctly before fully switching over.

We are currently ready for step six from the process listed below. I will change him onto Gmail at my next visit. Gmail spam filtering is working brilliantly and hasn't let a single spam into the inbox. I have had to tell Gmail that one or two senders are legitimate.

Please let me know if you see any problems with the process, and I will update.

The 8 step process:

1. Create a Gmail account

Create a new Gmail account that will become your long-term email address.

Continue using your Plusnet email as normal for now.

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2. Import existing mail into Gmail using POP

In Gmail:

1. Go to Settings → See all settings → Accounts and Import

2. Under Check mail from other accounts, select Add a mail account

3. Enter your full Plusnet email address

4. Choose Import emails from my other account (POP3)

5. Enter the Greenby POP server details

6. Ensure Leave a copy of retrieved messages on the server is enabled

This copies all existing mail into Gmail while leaving everything on the Greenby server as a backup.

Wait for the import to complete.

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3. Check Gmail spam handling

Once the import finishes:

• Review Gmail’s Spam folder

• Confirm that legitimate mail has not been incorrectly flagged

At this stage Gmail is effectively a copy of the Plusnet mailbox.

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4. Set up forwarding from Greenby to Gmail

Log into the Greenby control panel:

1. Go to Email → Forwarders

2. Add a forwarder for your main Plusnet mailbox

3. Add forwarders for any mailbox aliases as well

4. Set the destination address to your Gmail address

5. Leave Greenby configured to keep a copy of forwarded mail

New emails will now arrive in Gmail immediately, while still being stored in Greenby.

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5. Leave POP and forwarding enabled temporarily

It is safe to leave both POP retrieval and forwarding enabled at the same time.

Gmail avoids creating duplicates, and this ensures:

• No delivery delays

• No missed messages (important for verification emails)

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6. Start using Gmail as your main mailbox

Begin reading and replying to mail in Gmail.

Monitor spam filtering for a few days and adjust filters if required.

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7. Update contacts and online accounts

Gradually update:

• Contacts

• Mailing lists

• Banks and utilities

• Online services and subscriptions

So mail is sent directly to the Gmail address.

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8. (Optional) Disable POP later

Once you are confident that forwarding and Gmail are working reliably, POP retrieval can be disabled.

Forwarding alone is sufficient for ongoing mail delivery.

[#2]

In step 6 one can set up a reply-as address, i.e.as the original Plusnet address

[#3]

Certainly possible if someone wants to.

But, for us, since the intent is to migrate fully and have all contacts use the Gmail address ASAP, it is beneficial for the from address to change to Gmail immediately.

(IMO)

[#4]

Bear in mind that Google is ending support for GMail checking other email accounts. Supposedly it ended last month, but it still seems to be working for now (for me anyway). They can literally be pulling the plug at any time now. 

https://support.google.com/mail/answer/16604719?hl=en

[#5]

Yes, thanks. Also mentioned by  @grafter in another thread. Thanks both for the heads up.

So - Anyone who finds that their gmail account no longer supports POP 3 has the following options that I can see:

1 - Use a different service that supports POP.

2 - Find an alternate way to transfer old emails. The best might be to use a desktop client (like thunderbird). Connect to both the new gmail account and the old greenby account via imap, and then manually drag/drop all emails from one account to the other. I haven't tried this, and I think it likely that you would lose gmail spam filtering on the transferred emails this way. It might also be better to first copy from Greenby to a local thunderbird folder, then from that folder to Gmail. You could also decide just to keep the old emails in the local folder, and not bother transferring to Gmail.

3 - Abandon old emails. Leave them in Greenby until the 2 year free period is up, and then let them expire. Think of it as de-cluttering your life 🙂


Note that POP3 is only needed for step 2 - transferring old emails. Step 4 (Forwarding new mails from Greenby) will still work even when POP3 is turned off by Google.

[#6]

Gmails support timeline for withdrawing POP3 and direct 3rd party email support

What is the timeline?
We'll stop support for new users by the first quarter of 2026. Existing users can still use the feature until it's turned down later in 2026.

[#7]

Hi, I was already fetching from plusnet to gmail but in trying to set up the forwarding instead I ran into a couple of issues - choosing 'forward' does not seem to give any options (such as keep on server) so, following the instructions by greenby I did it via a filter in roundcube where you can - result seems to be that forwarding fails and greenby (bot) suggests this is a DKIM problem (which apparently BT also has?).  This only applies if you are using a desktop and web browser (and unfortunately that is how I do this not on a miniscule mobile that I can't see!).  Did I miss something or am I scuppered when gmail drop the fetching?

S.

[#8]

In my use case, I had been having Gmail fetch a copy of my PlusNet email since forever. When I learned Google was ending support for this last year I looked into alternatives. From what I read online there isn't any easy solution to the DKIM issue because Google really don't want you to do this. You basically need the knowhow to set up servers and such i.e. if you have your own domain or some means to relay the email somehow. Otherwise, even if you can get emails to forward, there is supposedly a high risk that you get blacklisted when your PlusNet/Greenby email forwards spam to Google.  

No joy for me. Only thing I can do is workaround by setting up a separate account in my mobile Gmail app to check the PlusNet account over IMAP as well, which is not the same thing. It's also a bit wonky sometimes, but I think that's down to the PlusNet servers. 

Maybe someone else can come up with a easy-to-follow set of instructions but it isn't going to be just setting up your existing emails in a certain way. It almost certain requires some third-party thing to work. 

Google doing this + PlusNet migrating emails to Greenby + BT ending support for copper... It's really quite stressful that all of these are happening at the same time! 

[#9]

@solent2 

If you use the forwarders in the "My greenby" settings the emails are also on left on the greenby server. It is similar to manually forwarding an email in roundcube. And much more reliable than the sieve filters.

You just need one forwarder for each mailbox and alias.

[#10]

See my post above. You should be able to use a desktop client like thunderbird with an iMap connection to both greenby and gmail and copy manually. I'd suggest via a local folder, rather than direct from one to the other.

[#11]

@tonycollinet 

Will your 8 steps work with Yahoo Mail?

[#12]

Yes, depending on how to transfer your old email into Yahoo. (step 2)

I've used Pop3 connection from Gmail to Greenby servers. I don't know if Yahoo can do this (Gmail soon will not) See my post above (Message 5) for alternative methods - or just start clean without your old emails.

Also - you'll need to check how good Yahoo is at filtering spam. (step 3)

[#13]

ok thanks, needless to say they didnt make that clear and their lovely bot is clever but also struggling with lack of input from greenby!

[#14]

@tonycollinet 

had a go at a straight forwarding from a mailbox rarely used but like the others gmail is silently blocking so they don't bounce just disappear into the ether

I always had thunderbird (and now betterbird) set up for pop3 not imap, can't remember now why that was better for my circumstances but am reluctant to change something now that has worked for me for decades.

[#15]

Anything identified as spam by Greenby is not forwarded - are you sure that is not happening?