Chime transcription service has stopped working due to permissions error

I have been using AWS Chime for recording and transcriptions for a few months with no issues and recently have encountered the following error:

AccessDenied: User: arn:aws:sts::xxxxxxxxxxx:assumed-role/dub3-audtincan1b-1-0-206368-0-TincanRole-J45O74OHLEA0/i-032700393d8f75ca2 is not authorized to perform: sts:AssumeRole on resource: arn:aws:iam::yyyyyyyyyy:role/aws-service-role/transcription.chime.amazonaws.com/AWSServiceRoleForAmazonChimeTranscription\n\tstatus code: 403, request id: 60b469d5-23a1-46fb-9a1e-7adc208f3b2b"

The first assumed assumed role seems to be generated by Chime and is not from my account. I am not sure why this error has only recently started to occur. Any advice would be appreciated.