POSIX 54 Error in Mail (iCloud Custom Domain)

I am so tired of Apple pushing out updates without fully trying them themselves. Now it’s the email not working. Also, since updating, I am having problems texting non-Apple users. I wish I never updated!

Yes I'm receiving this error message;

"The mail server "secure.emailsrvr.com" is not responding. Verify that you have entered the correct account info in Mail settings.

Network error (POSIX 54)"

Yes, the same thing is happening to me. I see that you're connecting to secure.emailsrvr.com, which is Rackspace. I also use Rackspace. And this just started with ios 18. Happens to both me and my wife. I reject the other replies in this thread. I don't think this has anything to do with iCloud servers since connecting to the Rackspace servers uses SMTP and does not utilize iCloud. Also, this has nothing to do with texting, RCS, or anything else people seem to be bringing up in this thread.

With me, its intermittent. If I ignore the error, eventually I stop getting it and it works fine.

I've reported it to Apple. I'm also going to report it to Rackspace since it may be an issue with one of their SMTP servers. Actually, I suspect this is the most likely scenario.

It's on Apple Servers and it can only be fixed by Apple. I have read that Apple Engineers know about it but no time line for a fix.

Rackspace is aware of the issue. This screenshot is from my Rackspace admin account. Their suggested workaround, i.e., using Webmail, doesn't really help because their Webmail is not set up to be responsive to small screens, so its pretty much unusable.

Well spotted, yes I use RackSpace Email. The issue is intermittent, annoying and I hope fixed soon!

It may be a coincidence, but so far, I only seem to be experiencing this when using WiFi. I tried a few different WiFi networks and it happened on all of them. I haven’t seen the issue on cellular.

Having the same issue with iPad OS 18.1

Definitely not happy about this, I hope that Apple fixes this problem soon.

Update: I chatted with a Apple support rep and had me trouble shoot it:

- turned off iCloud email in iCloud settings.

- force restarted iPad

- turned iCloud email back on in settings

Email is now working and the error has disappeared since!

I bought a new iPad with 18.0.1 a few weeks back, and I just got the POSIX 54 error for the first time today. But I am connecting to my gmail email account, not iCloud or any of the other mail servers also discussed in this thread.

I can still access my gmail via my desktop, Samsung phone, and even on the iPad by using Safari to log into the gmail account. But not working with email account defined on the iPad.

Using SE 2020 version and Rackspace. I’ve tried everything to fix issue. Here’s the only thing that worked: Quit Apple Mail and Restart iPhone. This fixes issue for a few hours or even a few days. If I get error code again, just restart again. It should be fixed in next iOS update.

TEXTing non iphones - like android - 18.X added RCS (carrier controlled) texting, and this is a mess. Turn RCS OFF on your iphone. when I did that, my SMS/MMS texts started to go through properly.

Never mind - I just got the error over 5G as well. :(

Having the same issue with iPad OS 18.1

Definitely not happy about this, I hope that Apple fixes this problem soon.

Glad it worked for you. I don't use iCloud mail, so that isn't the definitive solution.

My only recommendation would be to remove the email account and then force restart your device, as I did, then readd the email account, as it might help and follows a similar process.

Good luck!