Connectivity issues on my iPhone 16 Pro Max after iOS 18.3 update

Please reset your network settings, followed by a forced restart of your iPhone.

Reset your network settings

If you're using iOS or iPadOS 15 or later, tap Settings > General > Transfer or Reset [Device] > Reset > Reset Network Settings.

If you're using iOS or iPadOS 14 or earlier, tap Settings > General > Reset > Reset Network Settings.

This also resets Wi-Fi networks and passwords, cellular settings, and VPN and APN settings that you've used before.

Force restart iPhone - Apple Support

I had this problem on my iPhone 16 pro max. Didn’t matter what WiFi network I was on the download speed never would go above 30mbps upload never above 15mbps and those speeds were never solid. Would drop video streams constantly and pages would fail to load. I tried everything before arriving at the fix which was a huge time suck. The only way I found to fix the issue was to erase all content and settings and rebuild my phone from scratch. Restoring from backup by either method iCloud or direct device transfer would both carry the problem over. The only way to get the fix was to rebuild my phone from scratch downloading each app and restoring all my settings manually. It did work though. Just make sure you have access to all of your accounts that require 2fa before you do so because that is the most tedious and risky task involved with creating a brand new profile. My speeds and reliability on the device are now steady and consistent. I hope they hot fix it for everyone else who is experiencing this issue because starting over fresh is a pain in the butt.

UPDATE# After the 18.3.1 update, the WiFi issue was corrected. Thank you Apple 😎

Sorry. You didn’t mention having reset network settings. 😀

Does your iPhone have issues on all WiFi networks or just your home network?

Have you talked to your ISP? That’s really the first step. I have Spectrum and their app allows a reset and sometimes that resolves it. Sometimes I unplug the cable modem and router for 5 to 15 minutes. During that time I’ll reset network settings and it works. Once or twice, after doing all that, I’ve had to call tech support at Spectrum and it’s fixed with an hour or so.

Yup, it was an Apple problem, sent it back and they fixed… Not happy about this, one week without a work phone and no solution in between …

What did the carrier say when you talked to their support team member? Does your iPhone connect to any WiFi, like at a Starbucks etc.?

I have an iPhone 15 ProMax. After the iOS 18.3 update, my WiFi drops connection. My router has both 2.4 and 5 ghz options. It seems the phone will hold 2.4ghz better. Please fix this Apple.

For what it’s worth I started having the same issues after 18.3 on iPhone 15 Pro Max. Along with several laggy browsing along with this post. There is severe lags just typing this message out. Apple been really ******** the bed with its software lately.

I’m having the same problems. It’s ridiculous. I also noticed that when I was trying to search in my text messages it wasn’t pulling anything up either. Done 5/6 resets and nothing. Cleaned up space and nothing. Battery life is also draining in a third of the time. They need to fix this now.

Same problem with me too.After updating to 18.3.2 my 5G is not available on my iPhones.

becoming very reluctant to do updates from Apple until letting time go by to make sure there are no bugs in it.

Actually it’s not considered a best practice to remove SIM cards from one device to another. Various fraud schemes surround SIM cards, so I wouldn’t be surprised to learn carriers are enacting various security measures.

I don’t work for a carrier and never have but worked enough around Verizon cellular technicians to know the carrier needs to be involved in most solutions.

Have you talked to your carrier and if so, what did they say?