Base box 2 wireless connectivity Issue

I have problem.
I share internet with 2 two uses using mikrotik gr3 configure HotSpot on gr3 and for the wireless connectivity I use mikrotic basebox 2, 15 dbi antena on ch0, 11 dbi on ch1.
Problem is this , first client device , not connect easily,
On wifi connection error, ip assigning ip assigning.
If connection estibilished then slow speed on client end.
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