Форум спільноти Firefox для Android

as described, send tab function does not work one way (android to PC), but works fine from PC to android mobile phone/tablet. the pop-up error is the "Unable to send - RETRY", and pressing 'RETRY' doesn't do anything. I am logged in to the mozilla account on both android devices, and firefox sync/syncing tabs work fine. not sure what's the issue

Firefox Nightly -both phone and tablet: 127.0a1 (Build #2016019535) Firefox version -laptop: 125.0.3

I am migrating to a new phone. WhatsApp offered firefox as an option for storing its passkey. That took me to the connection and synchronisation process which the new phone said had failed. However all my tabs and other passwords appear to be syncing. Now selecting firefox to store the WhatsApp passkey takes me back to the failure page every time. Any idea how to restart the passkey addition to firefox process? WhatsApp won't work whilst I'm hung up in limbo between the two apps.