Hawaiian Airlines continues to experience intermittent issues with its online reservation systems and high customer call volume after an unexpected surge in demand to book and rebook travel.

A banner on Hawaiian’s website today said, “Our Contact Center is experiencing extended wait times to speak to a representative due to a high volume of calls. Guests without an immediate need to change a reservation should contact us at a later time. We apologize for the inconvenience and appreciate your patience.”

The banner said customers could still search and book flights. However, some customers have reported problems.

Hawaiian Airlines spokesman Alex Da Sila said the airline made “substantial progress over the weekend to improve our website performance.”

“Travelers should be able to book flights without issues, and if they encounter an intermittent error we advise that they wait an hour and try again.”

Hawaiian first notified HawaiianMiles members of the problems on Friday. The carrier asked for patience as it addressed the challenges that many customers were having “logging into digital accounts or getting through at an agent at a contact center.”

Hawaiian told customers that the technology team was working night and day to solve performance issues on HawaiianAirlines.com. The notice also said the contacts team was training new agents and staffing up its call center.

“Neither of these things has progressed as quickly as we had hoped and will likely not be fixed overnight. We know we have disappointed you and need to do better,” the notice said. “It is frustrating that this is happening at a time when we are so excited to welcome you back to travel. Now is the time we most want and need to be there for you. In the meantime, we apologize and humbly ask for your patience.”

Hawaiian’s system problems have come just as the carrier has begun to turn the corner.

Hawaiian saw gains in close-in travel demand from North America during March but posted a significant first-quarter loss largely due to a slow start to the year.

The airline, which operates under the publicly traded holding company Hawaiian Holdings Inc., reported a first-quarter loss of $60.7 million, or $1.25 a share. The carrier’s adjusted first-quarter loss this year was $190.6 million, or $3.85 a share. When adjusted for nonrecurring costs, first-quarter diluted earnings were $1.23 a share.

The company reported first-quarter revenue of $182 million. That’s down more than 67% from $559.1 million in revenue in the first quarter of 2020, when all the pandemic-related turbulence began.

Peter Ingram, Hawaiian Airlines president and CEO, told investors during the company’s first quarter earnings call late last month that the carrier began to see a “material improvement” in bookings for its North America routes as virus case counts began cresting in the U.S. in mid-January, even before the pace of vaccinations accelerated.

“Week by week for the rest of the quarter, the bookings pace continue to accelerate. Neighbor island bookings also improved, although not as much relative to pre-pandemic levels as North America,” he said. “If there was any doubt there is pent-up demand for leisure travel after a year of lockdowns, that doubt has now been dispelled.”