Check your Apple settings. I don’t recall offhand which it is, but it isn’t (or in the past, hasn’t been) Sonos asking for that data. 

Try the solution in the following thread:

I’ve worked out why AirPlay is asking me for a password now. This may not be everyone’s issue but my iPhone is company issued and they have recently tightened their Mobile Data Management security settings to request a password if AirPlay is requested. Not sure how this protects the company but it means I can’t connect my music to my Sonos beam anymore

Did you read the linked thread?

Separate link, but the Airplay on Sonos Restrictions and troubleshooting support page does mention the potential MDM restriction.

• iOS devices that have been issued by a company or organization may have Mobile Device Management (MDM) settings enabled that can restrict AirPlay. Contact your organization’s IT department for more information.

​@Brenunited - I suppose if a device was able to use the Airplay connection to somehow infiltrate your company iPhone then it would be a security risk, so your company has blocked that from potentially happening.