On a dual band access point, you can connect to wi-fi but there is no Internet access?

Question

WiFi

There is an Edimax WAP1200 access point in the office connected to the mikrotik hEx router. From time to time, a situation arises when, when connected to a 5 GHz network, the message "Connected, no access to the Internet" appears, and if from the same device it connects to the same access point, but to a 2.4 GHz network, everything works. Rebooting the access point helps, but then the problem repeats. according to the documentation, the access point should hold up to 100 users, in fact no more than 30 are connected. In the settings, additional connection quotas were not set.

Answer 1

according to the documentation, the access point should hold up to 100 users
What documentation did you find this in? The official one says up to 100 users of the 11ac standard (I doubt that you have all 11ac clients).
In the 2.4 band, you can get a maximum of 30 users at 2 megabits each. You can't argue against physics.
https://www.edimax.com/edimax/merchandise/merchand...
Edimax Pro series access points, with high-speed 11ac high-density networking for up to 100 simultaneous users
Possible problems
- DHCP problem, not addresses
- intersection channels, using the WIFI analyzer on Android, you can check
- the signal is too strong, the client must also be able to respond to the message. If the access point is stationary and has a stable power supply, it can afford to shine at 300 meters, then a smartphone that saves battery does not.
- there is a slow client, a client that sits far away and slows down the entire network. The solution is to reduce the signal level.
- if there is only one access point, check and disable the roaming option, many clients do not work with it correctly