China’s attempt to shift the world’s largest trade fair online this month has demonstrated that for some things, it’s hard to replace meeting face-to-face.

The Canton Fair, usually held in the southern megacity of Guangzhou twice a year, managed to get some 25,000 exhibitors to sign up for an online opportunity to “meet” global buyers. This took place through a virtual architecture built by Tencent Holdings Ltd featuring live streaming, translation, and conferencing technology.

But for many of the exhibitors interviewed by Bloomberg News over the past week, catching — and holding — the attention of browsing visitors online is much more difficult than in a physical setting. Communicating and following-up on leads afterwards was also more tricky in the virtual system.

“The online format definitely can’t replace the real fair for now, and I can’t see it happening even in one or two years,” said Yvonne Xu, a sales manager of Hangzhou Sinosky Industrial Ltd., a manufacturer of apparel and fashion accessories.

That is a sobering thought for technology optimists who hope that global commerce can shift quickly to operating online in an era where the coronavirus has curtailed global travel. China also needs sales now, as exports are down almost 8% this year so far and are scarcely expected to recover while the global economy remains in lockdown.

Like many other exporters, Ms. Xu’s company trained their salespeople in the weeks running up to the fair in order to be familiar with live video merchandising techniques. They also hired foreign models to make hundreds of photos for the online catalog. But the enormous hits they had expected from clients didn’t materialize.

Ms. Xu felt the virtual trade fair was still a new thing that hasn’t yet been accepted by foreign clients. In the real-world exhibition, customers come into a booth and can quickly spot the goods that interest them. In the live-streaming show, however, a salesperson would spend at least one or two minutes on each product and clients move on quickly if nothing catches their eye immediately.

While there’s a lot of visitor traffic, it is more difficult to get in touch with the clients compared with the old model, said Lilian Ho, a manager at the shoemaking company Wenzhou Steed International Industry Co. Ltd. “We have pages of visitor logs, but we can’t reach out to them as there are only names. Maybe that’s because of privacy concerns, but all I need is just an email address,” Ms. Ho said.

Ms. Ho missed the traditional fair, where a face-to-face conversation could quickly address clients’ questions, and salespeople would get hundreds of business cards for follow up later. In the virtual sphere, if a client doesn’t get a response within 30 seconds or so, they will likely exit, and it’s impossible to find them unless they leave their contacts or come back themselves.

The instant messaging tool is also not ideal, according to Bonny Chen, sales director at Hangzhou Shuaike Textile Import and Export Co., a manufacturer of leather clothing. Ms. Chen is happy with the visitor traffic — one live-stream session got over 1,800 viewers, inspiring her to seriously consider doing more online marketing via live-streaming apps in future. However, the communication is not smooth via the live chat tool as it sometimes lags, making typing text a burden for both sides.

Both Tencent and the Canton Fair organizers declined to comment on the feedback about the interface.

Admittedly, the live-streaming platform was built from scratch within two months. And the event was free of charge as the government was eager to support the export sector. Some smaller firms also did better than they expected.

Dayu Song, sales director at Zhejiang-based Haining Xinlong Seamless Garments Ltd. which exports yoga suits and sportswear, said her live-streaming sessions received over 1,200 visitors, six times her previous Canton Fair experience. In addition, 16 companies made serious inquiries, also a big jump from two or three in the past, she said.

The live-streaming site’s mysterious algorithm probably helped, as her company, without paying for any advertising, stayed at the top of the sportswear page for the first four days. That’s unimaginable in the real world where bigger manufacturers get bigger, better-designed booths and more attention.

”Despite all the hiccups in the system, we still think highly of the future of online fairs,” said Ms. Song. “Online fairs add one sales channel to a small factory like us and give us an opportunity to shine.”