Error logging in to matrix

I installed synapse a while ago and never took time to make it work. Today doing the setup everything seemed ok, I connected to https://synapse.mydomain.org which asked me some basic setup, then redirected to https://synapse.mydomain.org/_matrix/client/#/login and I created a user, logged in and all was fine.
But if I log out and try logging in again, I get the following error: synapse Internal server error (M_UNKNOWN).

I realized synapse wasn’t up to date and updated it from admin interface.
But it didn’t correct the problem.
Furthermore https://synapse.mydomain.org/_matrix/client/#/login now responds 404 (but https://synapse.mydomain.org/_matrix/static/ says everything is ok). Has the matrix default client been removed in the update?

I also tried from riot, and the issue is the same, I can create any user I want, it all works fine, and I can communicate with anyone until I log out. I just can never login again because of this error.

Reinstalling synapse solved the issue :confused: :slight_smile: