Yes, you can trace it.
There are a lot of things that can go wrong. And sometimes no clear solutions.
Exactly which model TC and what firmware.
I am trying to read betweeen the lines for the model.. I am going to guess for a Gen1-4 rather than new AC.. looking at the ages of most of your equipment.
First step.. go back from 7.6.4 firmware which is poor to 7.6.1 or even earlier, 7.5.2 depending on the model.
Full factory reset of the TC.. then clean new setup.
Use all SMB naming.. short no spaces and pure alphanumeric.. for TC and wireless.. even set different names to both bands so you can better track if one band or the other is the problem.
Then fix the channels.. 11, 6, 1 for 2.4ghz
36, 40, and then >149 for 5ghz.. although that is less of an issue.
Taking away as much of the auto voodoo as possible gives you more hope in tracking the issue.
Next is using the older 5.6 airport utility.. One of your computer must be able to run 5.6, the PC at least.. will. Then you have access to log in the TC.. v6 has no log access.
If the TC is more than 3years old.. very sadly they become unreliable.. particularly the Gen1 and Gen2 will burn out the power supply.. but even Gen3 is not reliable where they fixed the power supply and introduced new board issues with change to ceramic capacitors from excellent Tantalum in earlier ones.
