Firefox sync fails to connect to the server.

Firefox sync has not been working on my laptop for the past few days. It fails with the error "Failed to connect to the server. Sync will automatically retry this action." Sync is working fine on my Android device on the same network. I tried to disconnect and reconnect my sync account and also tried to sync in safe mode without any success. The error report from the sync log: https://pastebin.mozilla.org/8834320. In about:config the services.sync.clusterURL is not set. services.sync.tokenServerURI is set to the default value "https://token.services.mozilla.com/1.0/sync/1.5"