'Error: Connection Failure' on Android/iOS connection to custom LWS server- Cannot connect/create wallets

[CryptoGrampy]

Description

Connecting the latest Android/iOS MyMonero wallet to my custom LWS server results in an Error: Connection Failure alert when creating a new wallet. The Desktop app does seem to have a 500 error upon saving the custom server url, but seems to function totally fine (can create wallets / send tx's) despite this error. Additionally, the Android wallet is definitely calling the server (seeing some communication happening in the LWS logs, but no errors).

• [ ] Can you reproduce the issue?

Steps to reproduce

1. Specify my custom LWS URL in settings: https://mylws.myserver.myhost.com - there is a 'Connection Failure' error on saving the server address on Android, however there is an 'Unknown 500 error' when saving the LWS address from the desktop wallet.
2. Create a new wallet
3. Press 'Confirm' button on the Verify your mnemonic screen
4. Yellow connection failure alert pops up on the top, and wallet does not get created. On desktop wallet, the wallet gets created totally fine and can send tx's.

Expected behavior:

I expect a wallet to get created.

Actual behavior:

Remains on the Verify your mnemonic screen with the error at the top

Versions

• Mark Text version: 1.2.1 (I'm using the latest version from Github release, but the 'About MyMonero' says 1.2.1)
• Operating system: Android/iOS

One thing that seemed to be a little different from the Desktop app was the request headers:

Android:

2022-05-19 05:29:52.424 T HTTP HEAD:
2022-05-19 05:29:52.424 T Host: customlws.cool.grampyserver.com
2022-05-19 05:29:52.424 T User-Agent: Mozilla/5.0 (Linux; Android 12; Pixel 3 XL Build/SP2A.220505.002; wv) AppleWebKit/537.36 (KHTML, like Gecko) Version/4.0 Chrome/100.0.4896.127 Mobile Safari/537.36
2022-05-19 05:29:52.424 T Accept: */*
2022-05-19 05:29:52.424 T Accept-Encoding: gzip, deflate
2022-05-19 05:29:52.424 T Accept-Language: en-US,en;q=0.9
2022-05-19 05:29:52.424 T Access-Control-Request-Headers: content-type
2022-05-19 05:29:52.424 T Access-Control-Request-Method: POST
2022-05-19 05:29:52.424 T Origin: https://com.mymonero.android
2022-05-19 05:29:52.424 T Referer: https://com.mymonero.android/
2022-05-19 05:29:52.424 T Sec-Fetch-Dest: empty
2022-05-19 05:29:52.424 T Sec-Fetch-Mode: cors
2022-05-19 05:29:52.424 T Sec-Fetch-Site: cross-site

Desktop:

2022-05-19 05:32:55.274 T HTTP HEAD:
2022-05-19 05:32:55.274 T Host: customlws.cool.grampyserver.com
2022-05-19 05:32:55.274 T User-Agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) MyMonero/1.2.7 Chrome/83.0.4103.122 Electron/9.4.4 Safari/537.36
2022-05-19 05:32:55.274 T Content-Length: 74
2022-05-19 05:32:55.274 T Accept: application/json
2022-05-19 05:32:55.274 T Accept-Encoding: gzip, deflate, br
2022-05-19 05:32:55.274 T Accept-Language: en-US
2022-05-19 05:32:55.274 T Content-Type: application/json
2022-05-19 05:32:55.274 T Sec-Fetch-Dest: empty
2022-05-19 05:32:55.274 T Sec-Fetch-Mode: cors
2022-05-19 05:32:55.274 T Sec-Fetch-Site: cross-site