Zwift connect fails - oauth-callback returns 500

Connecting Zwift from Settings > Connections fails. I log in at
Zwift and approve, then the redirect to /api/zwift/oauth-callback
returns:

{“status”:500,“error”:“Internal server error, trace c3781746”}

Second attempt, incognito window:

{“status”:500,“error”:“Internal server error, trace 4fc88870”}

Tried: normal window, incognito, fresh login each attempt, no
refresh or back button. Logging into zwift.com directly works fine.
No Zwift connection appears on my account afterwards.

Thanks!

was able to solve it myself with the good ole restart computer and clear cookies method