POSIX 54 Error in Mail (iCloud Custom Domain)

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.

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!

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.

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.

I’ve been getting this error, I found that coming off WiFi and using 5g to update my mail then going back to WiFi clears the error.

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!

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.

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!

I’ve deleted all email accounts and then added them again without solving the issue sadly.