improve error handling

- [x] error message should not disappear. when opening the URL https://graphhopper.com/maps/?point=4.071167%2C-57.851562&point=48.479322%2C4.199219 it should state the error message but it disappears.
- [ ] sometimes with enabled custom model (slower responses) the previous error message come in from previous longer taking requests
- [x] https://graphhopper.com/maps/?point=-5.584508%252C-50.644531&point=45.235281%252C6.835937
- [x] bug if first hint is identical to message -> "and and" for https://graphhopper.com/maps/?point=3.369528%2C-55.917968&point=25.986478%2C5.429688&