Can't save an iRule because of formatting issues.

you cannot use HTTP:: command in CLIENT_ACCEPTED. change to HTTP_REQUEST event and it looks okay here.

root@(ve11a)(cfg-sync In Sync)(Active)(/Common)(tmos) list ltm rule qux
ltm rule qux {
    when HTTP_REQUEST {
  if { [class match [IP::remote_addr] equals O365_Microsoft_Networks_dg] } {
    if { ([HTTP::uri] contains "/ews")} {
      pool O365_POC_Exchange_owa_pool7
    }
  }
}
}