I want to say that I just started having this same problem. It used to be intermittent, but now it is consistent. Tasker has no problem issuing an HTTP request over local Wi-Fi to Hubitat Cloud APIs, but when I'm on the G5 Google Fi network, I get the following error.
As this is supposed to open my garage when I'm nearing the house and I scan an NFT in my car where Wi-Fi is not available, this has become a real inconvenience.
I saw you thought using the depreciated GET rather than REQUEST might help, but it did not. Did you find a solution?
To contribute: I we-wrote the Hubitat Application to see if there was some corruption, but it didn't help. I'm going to try putting the URL in a browser, and I'll report back.
Ok, I'm an idiot. I went to test the functionality by putting the URL in the web browser and I realized my cell connection was off. (See picture below). I don't know how long this was the case (guess I'm on Wi-Fi so much I didn't notice). Anyway, there doesn't seem to be any issue with Hubitat. If anything, the Tasker error should be updated to say something like, "hey, you're not connected to a network."
You can actually have tasker ping before running actions to determine if you have network. I use this to wait for a network connection when switching to automate whether or not my wiregaurd client kicks in.
Create a Ping Test Task that stores the result in a variable. I have mine set to try 5 times at 10 second intervals before giving up. That is what the ctrloop variable is about.
Call that task before you need to verify internet capability and use the results of the test to determine what to do. (i.e. No internet, flash a message and exit). In my case, whenever my wifi network disconnects, I wait a few seconds and then ping google. If successful, and I am not on my home network, then it connects wireguard. If I am on my home network (or other ones I have designated), it does not initiate wireguard.
NOTE: IMPORTANT TO CAPITALIZE THE first letter of the InetConnected variable (whatever you name yours). This makes it a GLOBAL variable that is available to other tasks. Lower case variables will only work within the task they were created in.
You might already be aware of that. But figured it would not hurt to say in case you did not.