Motorola Moto E — Connected, No Internet Problem

I have a Moto e5 Cruise(from Cricket Wireless), but I have no regular cell service, instead, I'm connecting to the Internet using only my AT&T Wi-Fi. About 2 months ago, out of the blue, my phone started dropping my connection to the Internet, randomly. My Wi-Fi signal indicator in my toolbar will just show a little "X" and when I go to my settings menu, I see an error msg saying: "Connected, no Internet". I thought it was a problem with my router, so AT&T replaced it with an updated, new model & had a tech come out to check the wiring, inside & outside. However, I'm still having the problem. My phone is the only one that is having the problem, so by process of elimination, I'm guessing it must be something with my device. I have double & triple checked that all the settings match between my device & my Wi-Fi settings, such as the Wpa Key, password, static, etc. I don't know what I'm doing wrong & obviously I'm not very technical. Can someone PLEASE help me figure out how to fix this super annoying problem...IN LAYMAN'S TERMS, PLEASE? I read somewhere that if you uncheck the box in the "Cricket Wi-Fi Connection Manager" that it will solve the problem, however, I've tried it both ways & I still have the same problem. Plus, like I said earlier, I no longer have service through Cricket, or any other carrier on this device, so I don't even think that part would apply to me at all. Thanks for any help/advice anyone can offer.