Cannot re-enable sliding-sync after the client was logged out

[MichaelSasser]

Steps to reproduce

1. sliding-sync is enabled and working properly
2. log-out, clear browser cache
3. log back in and try to enable sliding-sync
4. the SS button in labs is disabled and shows "Your server lacks support"

Outcome

What did you expect?

Sliding-sync can be enabled just like before / works like in my other sessions (in other web browsers), where sliding-sync is still enabled and working.

What happened instead?

The client doesn't allow me to enable sliding sync and tells me "Your server lacks support"

Additional information

client well-known

Initially, sliding-sync was configured before element-web read the client well known (matrix-org/matrix-react-sdk#12307) and the client has been updated regularly since then.

The client with the issue only shows the following line in the logs. The working ones continue with Sliding sync activated at https://matrix.michaelsasser.org/sliding-sync.

getProxyFromWellKnown: client well-known declares sliding sync proxy at https://matrix.michaelsasser.org/sliding-sync rageshake.ts:77:16

Operating system

Arch Linux

Browser information

Mozilla Firefox 127.0.2

URL for webapp

https://element.michaelsasser.org

Application version

vectorim/element-web:v1.11.69

Homeserver

ghcr.io/element-hq/synapse:v1.109.0

Will you send logs?

Yes

[t3chguy]

The sliding sync MSC provides an absolute path, which means sub-directory hosting is not supported. I suggest you get the MSC to change that. Related matrix-org/matrix-react-sdk#12658