Jwt authentication error

I am getting this error in the console. I have seen all the answers in several posts and the config files are saved the way explained in the posts.

I also see this error in prosody log…repeating every 5 seconds:
Jun 02 13:15:44 c2s5593982dc7e0 error Traceback[c2s]: /usr/lib/prosody/util/cache.lua:66: table index is nil
stack traceback:
/usr/lib/prosody/util/cache.lua:66: in function ‘set’
/usr/lib/prosody/modules/muc/mod_muc.lua:176: in function ‘track_room’
/usr/lib/prosody/modules/muc/mod_muc.lua:204: in function </usr/lib/prosody/modules/muc/mod_muc.lua:191>
(tail call): ?
/usr/lib/prosody/modules/muc/mod_muc.lua:433: in function ‘?’
/usr/lib/prosody/util/events.lua:79: in function </usr/lib/prosody/util/events.lua:75>
(tail call): ?
/usr/lib/prosody/core/stanza_router.lua:180: in function ‘core_post_stanza’
/usr/lib/prosody/core/stanza_router.lua:127: in function ‘core_process_stanza’
/usr/lib/prosody/modules/mod_c2s.lua:282: in function ‘func’
/usr/lib/prosody/util/async.lua:127: in function </usr/lib/prosody/util/async.lua:125>