IBS-M2 "offline" however all three temperature sensors are visible

What do I do to get the IBS-M2 back online? I don’t understand how it can be offline while the temperature sensors are working.

The IBS-M2 is literally 25" from the router that has 2.4 mhz band.

Just to confirm, on the INKBIRD APP homepage, does it show IBS-M2 offline? But the IBS-M2’s screen will display connected sensor readings?
Are there any obstacles between the IBS-M2 and the router?
Please make sure there is no limit on the number of connected devices to the router.

Thank you for the reply. I have checked everything you mentioned before I wrote to you, but I appreciate it.

When I place the IBS-MS and all 3 IBS-TH2 sensors within inches of the router, they work fine. The problem is that the sensors can be only a few feet away from the IBS-MS. They keep going off line intermittently. How can that be fixed? I’ve never owned a product with such short range.

Thank you for your time.

Kind regards,