The 24-year-old said the International Tennis Federation (ITF) had charged him in early 2022 for having missed three "out of competition test attempts" during a 12-month period.

"I fought that charge at a hearing, and was cleared by an independent tribunal of 3 arbitrators in June of 2022," he said on Twitter.

However, the ITF appealed the decision to the Court of Arbitration for Sport (CAS), which ruled in favour of the ITF.

CAS noted in a statement that Ymer had conceded to two "whereabouts failures" but contested a third instance, arguing that the doping control officer "did not make a reasonable attempt" to locate world number 51 Ymer - who was staying at a different hotel than originally planned.

The arbitration court however concluded that Ymer had "failed in ensuring his compliance with the anti-doping regulations by omitting to verify his whereabouts".

It added that he had assumed "any discrepancy between his actual and declared whereabouts would be corrected by his agent or by the tennis authorities."

At the same time, CAS opted for an 18-month suspension, rather than the two-year suspension requested by the ITF.

In his post to social media, Ymer lamented that he was banned "despite never having used nor been accused of using banned substances."

"Having already been cleared once, and wholeheartedly standing by the fact that I do not feel that the 3rd offence was committed, I find their decision to try me again and subsequently find me guilty, unfair," Ymer said.

Ymer was defeated in the third round of Wimbledon this year by Daniel Galan of Colombia.