10 common mistakes when using eSIM and how to fix them right away

eSIMs are convenient, but sometimes run into hiccups during activation or while traveling. Below are the 10 most common issues and simple solutions that anyone can fix on their own in 2-5 minutes.

1. Can't scan the QR code. Cause: the QR code is too small or blurry, or the camera doesn't have enough light. Solution: enlarge the QR code on another device's screen, hold your phone 15-20cm away, and make sure there is enough light. Alternatively, manually enter the SM-DP+ address and Activation code from Airalo/Saily.

2. Activated but no signal. You may not have arrived in Vietnam yet. A travel eSIM only gets signal once your plane lands in the destination country. If you're already in Da Nang: Settings → select eSIM Vietnam → Enable data roaming. Restart your phone.

3. There is signal but you can't access the internet. Check that "Mobile Data" is turned on for the correct eSIM. Go to Settings → Cellular Data Options → select eSIM Vietnam. Check that the APN is correct: Viettel is "v-internet", Vinaphone is "m3-world", MobiFone is "m-wap".

4. Slow internet, can't watch videos. You may be in an area with weak coverage (Hai Van Pass, the mountaintop at Ba Na). Or your data plan has used up its priority allowance (some plans slow down after a few GB). Check your remaining data in the Airalo/Saily app.

5. Can't receive calls/SMS. Data-only travel eSIMs cannot receive calls or SMS. If you need bank OTPs, you must keep your main SIM on with SMS roaming enabled (or use Google Voice or WhatsApp Call for calls).

6. Data runs out sooner than expected. This is due to automatic app updates and background streaming. Go to Settings → Cellular Data → turn off background app refresh for data-heavy apps (Netflix, YouTube, iCloud Photos, Google Photos backup).

7. Accidentally deleting the eSIM. A deleted eSIM cannot be restored. You'll have to contact Airalo/Saily support to request a re-issued QR code (this usually takes 1-2 hours, and sometimes you may need to buy a new plan). Tip: take a screenshot of the QR code and save the SM-DP+ address before activating.

8. Switching phones while in use. An eSIM doesn't automatically move to a new phone. You have to ask the provider to transfer the eSIM — which takes 24 hours — or buy a new plan. If you switch phones mid-trip, buying a new eSIM plan is faster than waiting for a transfer.

9. I have an eSIM, but my main SIM isn't working. If your phone doesn't support Dual SIM, it only allows 1 active SIM. Go to Settings → SIM Manager and turn on both SIMs. iPhone supports 1 nano SIM + 1 eSIM active at the same time, while Samsung S23+ supports 2 active eSIMs.

10. Your phone doesn't support eSIM. iPhones older than the XS, Samsung Galaxy S models older than the S20, and most older Xiaomi phones don't have eSIM. Check by dialing *#06# — if only 1 IMEI appears, your phone doesn't have eSIM. The list of supported devices is updated in post 10.

👉 Buy eSIMs from trusted sources to avoid errors: Choose major providers like Airalo/Saily at VietSpots eSIM Vietnam — with detailed activation instructions in Vietnamese and 24/7 support, reducing errors by 90% compared to buying unofficial eSIMs.

Quickly resolve eSIM issues — your trip never loses connection.