Moving e-mail to new host.

[#1]

I am a 74-year old who has had a domain hosted by Plusnet (in various guises) for more than 30 years.  Unfortunately, the hosting seems to be going wrong on a regular basis and when I try to send e-mails to groups, they get rejected with messages such as "Sending of the message failed.
An error occurred while sending mail. The mail server responded:
<aschjelderup@yahoo.co.uk> recipient rejected - too many recipient in last hour.
Please check the message recipient "aschjelderup@yahoo.co.uk" and try again." when I have been sending messages to this group for years.

Reluctantly, I have decided to move to another host.  When I contacted them, (Ionos), they said I need to get a transfer voucher from Plusnet so that they can take over the domain, but I don't where to start.  Help.

[#2]

Is your domain a .uk or a .com ?

The transfer procedure is different.

[#3]

Its a ".org.uk" and I've had it since 1977.

[#4]

In that case what Ionos is saying is rubbish. Here's the correct procedure https://www.ionos.co.uk/help/domains/domain-transfers-to-ionos/transfer-a-uk-domain-to-11-ionos/

Basically , you ask the new registrar to transfer your domain in. They provide you with their IPSTAG Name , you then change the IPSTAG via your existing registrar to that. With most registrars you can do that online via their control panel. I'm afraid the legacy PlusNet domain control system doesnt facilitate that. You need to ask Plusnet to change the IPSTAG for you. That can either be be calling customer services or wait for one of the Plusnet Help team to spot this thread and raise a ticket for you to provide the information. The procedure may take a few days...

[#5]

Sorry to be a pain, but I was just using Ionos as an example.  In fact, I have actually chosen GoDaddy to host my e-mail.  I suppose that the process is pretty much the same in that I have to get an authorisation code from Plusnet/Madasafish which I give to GoDaddy to enable the transfer process to begin?

[#6]

No! You do as I explained above.

Basically , you ask the new registrar to transfer your domain in. They provide you with their IPSTAG Name , you then change the IPSTAG via your existing registrar to that. With most registrars you can do that online via their control panel. I'm afraid the legacy PlusNet domain control system doesnt facilitate that. You need to ask Plusnet to change the IPSTAG for you. That can either be be calling customer services or wait for one of the Plusnet Help team to spot this thread and raise a ticket for you to provide the information. The procedure may take a few days...

The authorisation code (EPP) method ONLY applies to .com domains!. Here's godaddy's link to the procedure to transfer .uk domains https://uk.godaddy.com/help/about-uk-domains-5854

As an aside, I believe Godaddy charge for email on a per user (mailbox) basis , so if you use multiple mailboxes with your domain the costs can mount up. I suggest you check...