Image upload fails with '500 Internal Server Error' from Google (Python bridge)

[jcromero]

Image uploads fail consistently with a 500 error from Google's upload endpoint.

Context:

• Fresh session created via incognito window (cookies extracted and updated via login).
• Text messages work fine.
• Small images (<500KB) fail consistently.
• Rebooted bridge, same result.

It seems like the Google Chat API upload endpoint might have changed or is rejecting the request format.

Logs:

[2026-02-06 11:43:25,265] [DEBUG@mau.as] Handling transaction 124691 with 1 PDUs
[2026-02-06 11:43:25,270] [DEBUG@mau.as] Finished handling transaction 124691
[2026-02-06 11:43:25,271] [INFO@aiohttp.access] 127.0.0.1 [06/Feb/2026:10:43:25 +0000] "PUT /_matrix/app/v1/transactions/124691 HTTP/1.1" 200 158 "-" "Synapse/1.132.0"
[2026-02-06 11:43:25,271] [DEBUG@mau.mx] Received Matrix event  from @user:example.com in !xxx:example.com
[2026-02-06 11:43:26,769] [INFO@maugclib.http_utils] Request to https://chat.google.com/uploads?group_id=[REDACTED]&alt=&key=[REDACTED]&upload_id=[REDACTED]&session_crd=[REDACTED_TOKEN]&upload_protocol=resumable returned unexpected status: 500 Internal Server Error
[2026-02-06 11:43:26,769] [ERROR@mau.portal.dm:tocLnkAAAAE-xxx] Failed handling Matrix message 
Traceback (most recent call last):
  File "/opt/mautrix-googlechat/lib/python3.9/site-packages/mautrix_googlechat/portal.py", line 919, in handle_matrix_message
    resp = await self._handle_matrix_media(
  File "/opt/mautrix-googlechat/lib/python3.9/site-packages/mautrix_googlechat/portal.py", line 1098, in _handle_matrix_media
    upload = await sender.client.upload_file(
  File "/opt/mautrix-googlechat/lib/python3.9/site-packages/maugclib/client.py", line 309, in upload_file
    res = await self._base_request(upload_url, None, "", data, headers=headers, method="PUT")
  File "/opt/mautrix-googlechat/lib/python3.9/site-packages/maugclib/client.py", line 668, in _base_request
    res = await self._session.fetch(
  File "/opt/mautrix-googlechat/lib/python3.9/site-packages/maugclib/http_utils.py", line 169, in fetch
    raise exceptions.NetworkError(
maugclib.exceptions.NetworkError: Request return unexpected status: 500: Internal Server Error