Also tried to upload from another source (slack.com)
recieved the following errors:
State: receiving Certificate (11)
=== CERTIFICATE ISSUED TO ===
Common Name (CN): *.slack.com
Organization (O): Slack Technologies, Inc.
Location (L): San Francisco
Country (C): US
State (ST): California
Basic Constraints: CA:FALSE, pathlen:10000
Key Usage: critical, Digital Signature, Key Encipherment
Subject Alt Name: slack.com *.slack.com
=== CERTIFICATE ISSUED BY ===
Common Name (CN): GeoTrust SSL CA - G3
Organization (O): GeoTrust Inc.
Country (C): US
Not Before: Wed Feb 1 00:00:00 2017
Not After: Fri Feb 1 23:59:59 2019
RSA bitsize: 2048
Sig Type: SHA256
=== CERTIFICATE ISSUED TO ===
Common Name (CN): GeoTrust SSL CA - G3
Organization (O): GeoTrust Inc.
Country (C): US
Basic Constraints: critical, CA:TRUE, pathlen:0
Key Usage: critical, Key Cert Sign, CRL Sign
Subject Alt Name:
=== CERTIFICATE ISSUED BY ===
Common Name (CN): GeoTrust Global CA
Organization (O): GeoTrust Inc.
Country (C): US
Not Before: Tue Nov 5 21:36:50 2013
Not After: Fri May 20 21:36:50 2022
RSA bitsize: 2048
Sig Type: SHA256
:rd 5, 157, 148
:rdi 9, 5
:rd 4, 157, 153
:rdi 4, 4
:c0 4, 157
State: receiving Server Hello Done (14)
State: sending Client Key Exchange (16)
:wr 267 267 0
:wrc 256 267 0
:wrc 11 11 0
:wr 6 6 0
:wrc 6 6 0
State: sending Finished (16)
:wr 85 85 0
:wrc 85 85 0
:sent 267
:sent 91
:rn 91
:rd 5, 91, 0
:rdi 91, 5
:rd 1, 91, 5
:rdi 86, 1
:rd 5, 91, 6
:rdi 85, 5
:rd 80, 91, 11
:rdi 80, 80
:c0 80, 91
State: receiving Finished (16)
[HTTP-Client] connected to files.slack.com:443
:ref 2
domain name: 'files.slack.com'
SAN 0: 'slack.com', no match
:ur 2
[HTTP-Client] sending request header
-----
GET /files-pri/T8PANAHHB-F8NGEG88G/download/test.ino.bin HTTP/1.0
Host: files.slack.com
User-Agent: ESP8266-http-Update
Connection: close
x-ESP8266-STA-MAC: A0:20:A6:15:D6:3E
x-ESP8266-AP-MAC: A2:20:A6:15:D6:3E
x-ESP8266-free-space: 2760704
x-ESP8266-sketch-size: 383872
x-ESP8266-sketch-md5: b4a547b95dcff1251ab045af0a82cdf8
x-ESP8266-chip-size: 4194304
x-ESP8266-sdk-version: 2.1.0(deb1901)
x-ESP8266-mode: sketch
-----
:wr 485 485 0
:wrc 256 485 0
:wrc 229 229 0
:sent 485
:rn 536
:rch 536, 157
:rch 693, 69
:rcl
:abort
:rd 5, 762, 0
:rdi 536, 5
:rd 688, 762, 5
:rdi 531, 531
:c 531, 536, 762
:rdi 157, 157
:c 157, 157, 226
:wcs ra 624
[HTTP-Client][handleHeaderResponse] RX: 'HTTP/1.1 302 Found'
[HTTP-Client][handleHeaderResponse] RX: 'Content-Type: text/html; charset=utf-8'
[HTTP-Client][handleHeaderResponse] RX: 'Content-Length: 118'
[HTTP-Client][handleHeaderResponse] RX: 'Connection: close'
[HTTP-Client][handleHeaderResponse] RX: 'Location: https://esp8266hq.slack.com/?redir=%2Ffiles-pri%2FT8PANAHHB-F8NGEG88G%2Fdownload%2Ftest.ino.bin'
[HTTP-Client][handleHeaderResponse] RX: 'X-Backend: imgproxy-bru-w0bj'
[HTTP-Client][handleHeaderResponse] RX: 'X-Slack-Meta: ?;proxy_redir'
[HTTP-Client][handleHeaderResponse] RX: 'Date: Sun, 07 Jan 2018 12:44:30 GMT'
[HTTP-Client][handleHeaderResponse] RX: 'Via: 1.1 google, 1.1 b74a7a3f7ddfd685212e870d027c332d.cloudfront.net (CloudFront)'
[HTTP-Client][handleHeaderResponse] RX: 'Alt-Svc: clear'
[HTTP-Client][handleHeaderResponse] RX: 'X-Cache: Miss from cloudfront'
[HTTP-Client][handleHeaderResponse] RX: 'X-Amz-Cf-Id: 7AHMYU0-9muQAHW7h1n378eAacj1IaSr_oQLpc1uHssJkh2lbscrGg=='
[HTTP-Client][handleHeaderResponse] RX: ''
[HTTP-Client][handleHeaderResponse] code: 302
[HTTP-Client][handleHeaderResponse] size: 118
[httpUpdate] Header read fin.
[httpUpdate] Server header:
[httpUpdate] - code: 302
[httpUpdate] - len: 118
[httpUpdate] ESP8266 info:
[httpUpdate] - free Space: 2760704
[httpUpdate] - current Sketch Size: 383872
[httpUpdate] HTTP Code is (302)
[HTTP-Client][end] still data in buffer (118), clean up.