I've got that issue too when I ordered the Umidigi F1 Play. To fix the issue, you need to change the APN setting of your phone by following the step by step APN configuration as described in the PM link below:
https://productioncommunity.publicmobile.ca/t5/Phones-Hardware/How-do-I-set-up-data-APN-on-my-smartp...
However, I strongly advise you to reconsider to buy a UMIDIGI phone from UMIDIGI official store on AliExpress. I bought UMIDIGI F1 Play and when I received the phone and try it, the sound quality at the earphone during a phone call / conversation was so bad and the overall quality was low (much worst than a MOTO E2). The last straw was their HORRIBLE customer service (no reply to mails, no phone number, unprofessional replies, etc.). Although the Umidigi Official Store policy on AliExpress has a "7 days no reason to return and refund", I have returned the phone to China which cost me about 90.00$. According to the Canada Post tracking, parcel has been successfully delivered to the specified return address in China. However, Umidigi official store stop replying to me and never refund me.One month later, still no refund.
Finally, I got my cash back only by opening a claim with AliExpress against Umidigi Official store. Sometimes, when you want to save money, it cost you more. UMIDIGI phones are the perfect example!
Conclusion: DO NOT BUY UMIDIGI phone because it is very low overall quality that will last about 1 year, 1 year of bad quality phone conversation... (260$ on AliExpress that last about 12 months). Instead, buy a good mid-range like Samsung Galaxy A50 that cost about 400$, but will last 24-36 months and is much much better overall quality (phone call, processor, AMOLED screen, etc. ). This what I did and I do not regret it. This is my lesson's learned!
