554 5.4 6 hop count exceeded possible mail loop
- 554 5.4 6 hop count exceeded possible mail loop hybrid
- Smtp 554 5.4 6 hop count exceeded possible mail loop
- Reason 554 5.4 6 hop count exceeded possible mail loop
- 5.3.0 - other mail system problem 554-'5.4.6 hop count exceeded - possible mail loop'
- Hop count exceeded - possible mail loop detected on message