Hello LongKPS,
We had the same problems. it turned out to have nothing to do with (ip) settings or DNS and everything to do with an error in the firmware. We did a downgrade to version 27.7.1 and the problems are over. Additional advantage: the automatic channel planning works much better.
This was Meraki's response a few weeks ago:
"" As this is still currently a known issue due to the changes in the way Meraki devices communicate to the Meraki cloud from MR 28.x + firmware, We can implement a temporary workaround of rolling back the firmware of the APs to a previous version 27.7.1 until the issue on 28.x+ firmware is resolved by engineering.""