II have a black shark as well and I am having the same problem. The only fix I have found is to uninstall epic seven, turn the phone off, wait a minute, turn it on, and reinstall. Repeat until it works. Might take 1 to 6 tries. But as soon as you log out, you'll have to do that process all over again unfortunately. I hope they fix this soon

I have the exact same problem with my Black Shark Helo 2. Issue appeared first after installing the latest OS Update from the "JOY UI" (G66T1906251CN00MPP). Have to play on my Tablet as workaround. Can't stress my data limit with the reinst process every time :( 

That said the lobby does not even show ingame events like finishing dispatch missions or login rewards. Switching to another server and playing the tutorial works fine up to the point where you enter the lobby for the first time... then it is stuck again

Any progress/solution/better workaround about this issue, yet? Kinda annyoing not beeing able to play E7, a mobile game, on my phone...

EDIT:

Alright guys since we might have to wait a bit for SG to tackle this issue I discovered another Workaround:

1) Close all Apps (the right to left and hold swipe-thingy)

2) Turn Off Phone and wait 1-2m

3) Start Phone

4) Log in to your Google Apps like Play Store, Gmail

5) Start E7 via Google Play App (not the store thing)

It worked for me a couple of times and has to be redone once you log off... also some steps might be unnecessary (but I'll do the anyways fo good charm). My guess on that issue is a communication issue between the E7 app, Google Play, and the E7 servers... after all its a CN Phone with manually installed google Stuff..

EDIT:

Seems like restarting the phone isn't needed. Just make sure to close E7 completely (forcfully), log in into google play store, log in into google game play, start E7 from within the google game play app

still no solution? i got the same problem after updating my system
black shark helo 

No proper solution yet, just a few workarounds to get the game to work. Ive sent a ticket in and they replied asking for phone information but have not replied back since. =\

Finally found people having a same problem as me, ye the latest update of black shark helo completely ****** up the game, not e7 alone but making the other games unable to access store to buy stuff with real money, hope they will fix it in the next update

My only way to get into the game on phone is when you tap to go into lobby, press your lock screen button right away to lock your phone then unlock, the down side is you can't access store and event page, i have to do it on emu.